Proto-Indo-European language

<h2 id="development-of-the-hypothesis">Development of the hypothesis</h2>
No direct evidence of PIE exists; scholars have reconstructed PIE from its present-day descendants using the <a href="/facts/Comparative_method_(linguistics)/VKJAa3zy">comparative method</a>.<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a> For example, compare the pairs of words in Italian and English: piede and foot, padre and father, pesce and fish. Since there is a consistent correspondence of the initial consonants (p and f) that emerges far too frequently to be coincidental, one can infer that these languages stem from a common <a href="/facts/Parent_language/BkXHmE3J">parent language</a>.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a> Detailed analysis suggests a system of <a href="/facts/Indo-European_sound_laws/09wNuAGu">sound laws</a> to describe the <a href="/facts/Phonetics/ljAVT8fv">phonetic</a> and <a href="/facts/Phonology/qWAsvnok">phonological</a> changes from the hypothetical ancestral words to the modern ones. These laws have become so detailed and reliable as to support the <a href="/facts/Neogrammarian_hypothesis/ukLnXQAl">Neogrammarian hypothesis</a>: the Indo-European sound laws apply without exception.
<a href="/facts/William_Jones_(philologist)/AxWH8Mda">William Jones</a>, an <a href="/facts/Anglo-Welsh/9mjb6TPC">Anglo-Welsh</a> <a href="/facts/Philology/5u0xzd5g">philologist</a> and <a href="/facts/Puisne_judge/dVLE0DvQ">puisne judge</a> in <a href="/facts/Bengal/xp3t2Dyd">Bengal</a>, caused an academic sensation when in 1786 he postulated the common ancestry of <a href="/facts/Sanskrit/ychfjhlx">Sanskrit</a>, <a href="/facts/Greek_language/pzDd6eIz">Greek</a>, <a href="/facts/Latin/pM3Kge85">Latin</a>, <a href="/facts/Gothic_language/14Hrn0o2">Gothic</a>, the <a href="/facts/Celtic_languages/edRrGrMF">Celtic languages</a>, and <a href="/facts/Old_Persian/gxx47Ul7">Old Persian</a>,<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a> but he was not the first to state such a hypothesis. In the 16th century, European visitors to the <a href="/facts/Indian_subcontinent/0XUWGXpx">Indian subcontinent</a> became aware of similarities between <a href="/facts/Indo-Iranian_language/uIfMNTQV">Indo-Iranian languages</a> and European languages,<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a> and as early as 1653, <a href="/facts/Marcus_Zuerius_van_Boxhorn/a6PqSuHW">Marcus Zuerius van Boxhorn</a> had published a proposal for a <a href="/facts/Proto-language/BkXHmE3J">proto-language</a> ("Scythian") for the following language families: <a href="/facts/Germanic_languages/BxAJX3Kf">Germanic</a>, <a href="/facts/Romance_languages/TMK4KHI3">Romance</a>, <a href="/facts/Hellenic_languages/8968kKo7">Greek</a>, <a href="/facts/Baltic_languages/Jmj2ckcI">Baltic</a>, <a href="/facts/Slavic_languages/b5GaeFx1">Slavic</a>, <a href="/facts/Celtic_languages/edRrGrMF">Celtic</a>, and <a href="/facts/Iranian_languages/JaJyqM4t">Iranian</a>.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a> In a memoir sent to the <a href="/facts/Acad%C3%A9mie_des_Inscriptions_et_Belles-Lettres/AwpCcz2n">Académie des Inscriptions et Belles-Lettres</a> in 1767, <a href="/facts/Gaston-Laurent_Coeurdoux/AqyVXqot">Gaston-Laurent Coeurdoux</a>, a French <a href="/facts/Jesuit/n0PeYBB8">Jesuit</a> who spent most of his life in India, had specifically demonstrated the analogy between Sanskrit and European languages.<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a> According to current academic consensus, Jones's famous work of 1786 was less accurate than his predecessors', as he erroneously included <a href="/facts/Egyptian_language/mSqys6jC">Egyptian</a>, <a href="/facts/Japanese_language/EEv485a5">Japanese</a> and <a href="/facts/Chinese_language/771ruUY1">Chinese</a> in the Indo-European languages, while omitting <a href="/facts/Hindi/n1QIEeCC">Hindi</a>.
In 1818, Danish linguist <a href="/facts/Rasmus_Christian_Rask/hVXIXmgc">Rasmus Christian Rask</a> elaborated the set of correspondences in his prize essay Undersøgelse om det gamle Nordiske eller Islandske Sprogs Oprindelse ('Investigation of the Origin of the Old Norse or Icelandic Language'), where he argued that <a href="/facts/Old_Norse/3dIvgsm5">Old Norse</a> was related to the Germanic languages, and had even suggested a relation to the Baltic, Slavic, Greek, Latin and Romance languages.<a class="footnote-ref" id="fnref:12" href="#fn:12">12</a> In 1816, <a href="/facts/Franz_Bopp/Uk1F5Mwf">Franz Bopp</a> published On the System of Conjugation in Sanskrit, in which he investigated the common origin of Sanskrit, Persian, Greek, Latin, and German. In 1833, he began publishing the Comparative Grammar of Sanskrit, <a href="/facts/Avestan/0b7tvGQs">Zend</a>, Greek, Latin, Lithuanian, Old Slavic, Gothic, and German.<a class="footnote-ref" id="fnref:13" href="#fn:13">13</a>
In 1822, <a href="/facts/Jacob_Grimm/6qdM4ksF">Jacob Grimm</a> formulated what became known as <a href="/facts/Grimm%27s_law/gnVnHs7J">Grimm's law</a> as a general rule in his Deutsche Grammatik. Grimm showed correlations between the Germanic and other Indo-European languages and demonstrated that sound change systematically transforms all words of a language.<a class="footnote-ref" id="fnref:14" href="#fn:14">14</a> From the 1870s, the Neogrammarians proposed that sound laws have no exceptions, as illustrated by <a href="/facts/Verner%27s_law/zT7ylWGn">Verner's law</a>, published in 1876, which resolved apparent exceptions to Grimm's law by exploring the role of accent (stress) in language change.<a class="footnote-ref" id="fnref:15" href="#fn:15">15</a>
<a href="/facts/August_Schleicher/MHhAmGEg">August Schleicher</a>'s A Compendium of the Comparative Grammar of the Indo-European, Sanskrit, Greek and Latin Languages (1874–77) represented an early attempt to reconstruct the Proto-Indo-European language.<a class="footnote-ref" id="fnref:16" href="#fn:16">16</a>
By the early 1900s, <a href="/facts/Indo-Europeanist/ExbGjgzD">Indo-Europeanists</a> had developed well-defined descriptions of PIE which scholars still accept today. Later, the discovery of the <a href="/facts/Anatolian_languages/aGWvRmue">Anatolian</a> and <a href="/facts/Tocharian_languages/zCILXC6E">Tocharian languages</a> added to the corpus of descendant languages. A subtle new principle won wide acceptance: the <a href="/facts/Laryngeal_theory/WzwJPK3U">laryngeal theory</a>, which explained irregularities in the reconstruction of Proto-Indo-European phonology as the effects of hypothetical sounds which no longer exist in all languages documented prior to the excavation of <a href="/facts/Cuneiform/MgIQoGu8">cuneiform</a> tablets in Anatolian. This theory was first proposed by <a href="/facts/Ferdinand_de_Saussure/NjS5SPBA">Ferdinand de Saussure</a> in 1879 on the basis of internal reconstruction only,<a class="footnote-ref" id="fnref:17" href="#fn:17">17</a> and progressively won general acceptance after <a href="/facts/Jerzy_Kury%C5%82owicz/xGUfutm1">Jerzy Kuryłowicz</a>'s discovery of consonantal reflexes of these reconstructed sounds in Hittite.<a class="footnote-ref" id="fnref:18" href="#fn:18">18</a>
<a href="/facts/Julius_Pokorny/qoSs6YNm">Julius Pokorny</a>'s <a href="/facts/Indogermanisches_etymologisches_W%C3%B6rterbuch/Fd1v99P8">Indogermanisches etymologisches Wörterbuch</a> ('Indo-European Etymological Dictionary', 1959) gave a detailed, though conservative, overview of the lexical knowledge accumulated by 1959. Jerzy Kuryłowicz's 1956 Apophonie gave a better understanding of <a href="/facts/Indo-European_ablaut/fphzPyba">Indo-European ablaut</a>. From the 1960s, knowledge of Anatolian became robust enough to establish its relationship to PIE.
In The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World, Mallory and Adams illustrate the resemblance with the following examples of <a href="/facts/Cognate/nXETf5Y4">cognate</a> forms (with the addition of Old English for further comparison):<a class="footnote-ref" id="fnref:19" href="#fn:19">19</a>

<table><tbody><tr><th>  PIE</th><th>  English</th><th>  Old English</th><th>  Latin</th><th>  Greek</th><th>  Sanskrit</th></tr><tr><td>*méh₂tēr</td><td>  mother</td><td>  mōdor</td><td>  māter</td><td>  mḗtēr</td><td>  mātár-</td></tr><tr><td>*ph₂tḗr</td><td>  father</td><td>  fæder</td><td>  pater</td><td>  patḗr</td><td>  pitár-</td></tr><tr><td>*bʰréh₂tēr</td><td>  brother</td><td>  brōþor</td><td>  frāter</td><td>  phrḗtēr</td><td>  bhrā́tar-</td></tr><tr><td>*swésōr</td><td>  sister</td><td>  sweostor</td><td>  soror</td><td>  éor</td><td>  svásar-</td></tr><tr><td>*suHnús, suHyús</td><td>  son</td><td>  sunu</td><td> -</td><td>  huiús</td><td>  sūnú-</td></tr><tr><td>*dʰugh₂tḗr</td><td>  daughter</td><td>  dohtor</td><td> -</td><td>  thugátēr</td><td>  duhitár-</td></tr><tr><td>*gʷṓus</td><td>  cow</td><td>  cū</td><td>  bōs</td><td>  boûs</td><td>  gáu-</td></tr></tbody></table>
<h2 id="historical-and-geographical-setting">Historical and geographical setting</h2>
Main article: <a href="/facts/Proto-Indo-European_homeland/r05Un7V0">Proto-Indo-European homeland</a>

Scholars have proposed multiple hypotheses about when, where, and by whom PIE was spoken. The <a href="/facts/Kurgan_hypothesis/Vrf8emue">Kurgan hypothesis</a>, first put forward in 1956 by <a href="/facts/Marija_Gimbutas/ltT2brqS">Marija Gimbutas</a>, has become the most popular.<a class="footnote-ref" id="fnref:20" href="#fn:20">20</a> It proposes that the original speakers of PIE were the <a href="/facts/Yamnaya_culture/NeNAqJx8">Yamnaya culture</a> associated with the <a href="/facts/Kurgan/4LcU3JeE">kurgans</a> (burial mounds) on the <a href="/facts/Pontic%E2%80%93Caspian_steppe/KzRVR1WW">Pontic–Caspian steppe</a> north of the Black Sea.<a class="footnote-ref" id="fnref:21" href="#fn:21">21</a>: 305–7 <a class="footnote-ref" id="fnref:22" href="#fn:22">22</a> According to the theory, they were <a href="/facts/Eurasian_nomads/DAsbkwqW">nomadic pastoralists</a> who <a href="/facts/Domestication_of_the_horse/XbRKqavo">domesticated the horse</a>, which allowed them to migrate across Europe and Asia in wagons and chariots.<a class="footnote-ref" id="fnref:23" href="#fn:23">23</a> By the early 3rd millennium BCE, they had expanded throughout the Pontic–Caspian steppe and into eastern Europe.<a class="footnote-ref" id="fnref:24" href="#fn:24">24</a>
Other theories include the <a href="/facts/Anatolian_hypothesis/ougGmfPI">Anatolian hypothesis</a>,<a class="footnote-ref" id="fnref:25" href="#fn:25">25</a> which posits that PIE spread out from Anatolia with agriculture beginning c. 7500–6000 BCE,<a class="footnote-ref" id="fnref:26" href="#fn:26">26</a> the <a href="/facts/Armenian_hypothesis/5XVqfgSC">Armenian hypothesis</a>, the <a href="/facts/Paleolithic_continuity_paradigm/r05Un7V0">Paleolithic continuity paradigm</a>, and the <a href="/facts/Indigenous_Aryans/RaIexbIF">indigenous Aryans</a> theory. The last two of these theories are not regarded as credible within academia.<a class="footnote-ref" id="fnref:27" href="#fn:27">27</a><a class="footnote-ref" id="fnref:28" href="#fn:28">28</a> Out of all the theories for a PIE homeland, the Kurgan and Anatolian hypotheses are the ones most widely accepted, and also the ones most debated against each other.<a class="footnote-ref" id="fnref:29" href="#fn:29">29</a> Following the publication of several studies on ancient DNA in 2015, Colin Renfrew, the original author and proponent of the Anatolian hypothesis, has accepted the reality of migrations of populations speaking one or several Indo-European languages from the Pontic steppe towards Northwestern Europe.<a class="footnote-ref" id="fnref:30" href="#fn:30">30</a><a class="footnote-ref" id="fnref:31" href="#fn:31">31</a>

<h2 id="descendants">Descendants</h2>
Main article: <a href="/facts/Indo-European_languages/L34TfgSr">Indo-European languages</a>
The antiquity of the earliest attestation (in units of 500 years) of each Indo-European group is: 2000–1500 BCE for Anatolian; 1500–1000 BCE for Indo-Aryan and Greek; 1000–500 BCE for Iranian, Celtic, Italic, Phrygian, Illyrian, Messapic, South Picene, and Venetic; 500–1 BCE for Thracian and Ancient Macedonian; 1–500 CE for Germanic, Armenian, Lusitanian, and Tocharian; 500–1000 CE for Slavic; 1500–2000 CE for Albanian and Baltic.<a class="footnote-ref" id="fnref:32" href="#fn:32">32</a>
The table lists the main Indo-European language families, comprising the languages descended from Proto-Indo-European.

<table><tbody><tr><th>Clade</th><th>Proto-language</th><th>Description</th><th>Historical languages</th><th>Modern descendants</th></tr><tr><td><a href="/facts/Anatolian_languages/aGWvRmue">Anatolian</a></td><td><a href="/facts/Proto-Anatolian_language/pUjSdq09">Proto-Anatolian</a></td><td>All now extinct, the best attested being the <a href="/facts/Hittite_language/Pc8YGhRU">Hittite language</a>.</td><td><a href="/facts/Hittite_language/Pc8YGhRU">Hittite</a>, <a href="/facts/Luwian_language/zlcGzPyy">Luwian</a>, <a href="/facts/Palaic/NBnndjYT">Palaic</a>, <a href="/facts/Lycian_language/9uotLqML">Lycian</a>, <a href="/facts/Lydian_language/6Qj2CC35">Lydian</a>, <a href="/facts/Carian_language/WufUyyKb">Carian</a>, <a href="/facts/Pisidian_language/Vrt2qsUN">Pisidian</a>, <a href="/facts/Sidetic_language/XRFNbFIf">Sidetic</a></td><td>There are no living descendants of Proto-Anatolian.</td></tr><tr><td><a href="/facts/Tocharian_languages/zCILXC6E">Tocharian</a></td><td><a href="/facts/Proto-Tocharian_language/UtqthfK0">Proto-Tocharian</a></td><td>An extinct branch known from manuscripts dating from the 6th to the 8th century AD and found in northwest China.</td><td>Tocharian A, <a href="/facts/Tocharian_B/zCILXC6E">Tocharian B</a></td><td>There are no living descendants of Proto-Tocharian.</td></tr><tr><td><a href="/facts/Italic_languages/82W676n0">Italic</a></td><td><a href="/facts/Proto-Italic_language/JgdplDSW">Proto-Italic</a></td><td>This included many languages, but only descendants of <a href="/facts/Latin/pM3Kge85">Latin</a> (the <a href="/facts/Romance_languages/TMK4KHI3">Romance languages</a>) survive.</td><td><a href="/facts/Latin/pM3Kge85">Latin</a>, <a href="/facts/Faliscan_language/61rQpvUN">Faliscan</a>, <a href="/facts/Umbrian/KdAMAJvc">Umbrian</a>, <a href="/facts/Oscan/DnrwH4an">Oscan</a>, <a href="/facts/African_Romance/IGNVcoaM">African Romance</a>, <a href="/facts/Dalmatian_language/xxNjkMkn">Dalmatian</a>, <a href="/facts/Volscian_language/HCtrS7Dw">Volscian</a>, <a href="/facts/Marsi/I1rkv57d">Marsi</a>, <a href="/facts/Pre-Samnite_language/6v5uFRmt">Pre-Samnite</a>, <a href="/facts/Paeligni/JuJzoBAL">Paeligni</a>, <a href="/facts/Sabines/7CPj2jJv">Sabine</a></td><td><a href="/facts/Portuguese_language/vr3Fwzw3">Portuguese</a>, <a href="/facts/Galician_language/bGIhIvMX">Galician</a>, <a href="/facts/Spanish_language/95BgYNfv">Spanish</a>, <a href="/facts/Judaeo-Spanish/agC0XUvz">Ladino</a>, <a href="/facts/Catalan_language/W2uTbK8Q">Catalan</a>, <a href="/facts/Occitan_languages/w0etTc3w">Occitan</a>, <a href="/facts/French_language/qe1DnaQh">French</a>, <a href="/facts/Italian_language/YXsmvlQG">Italian</a>, <a href="/facts/Friulian_language/2nFd3v8K">Friulian</a>, <a href="/facts/Romansh_language/KrxKLUlk">Romansh</a>, <a href="/facts/Romanian_language/zAY3GnkL">Romanian</a>, <a href="/facts/Aromanian_language/bsEyJ9PY">Aromanian</a>, <a href="/facts/Sardinian_language/KvJhFVLn">Sardinian</a>, <a href="/facts/Corsican_language/QjwJhhJt">Corsican</a>, <a href="/facts/Venetian_language/FeaL1TE9">Venetian</a>, Latin (as a <a href="/facts/Liturgical_language/557K2NXD">liturgical language</a> of the Catholic Church and the official language of the <a href="/facts/Vatican_City/JTKnEt6J">Vatican City</a>), <a href="/facts/Picard_language/1RkE2uRx">Picard</a>, <a href="/facts/Mirandese_language/zzmezR0z">Mirandese</a>, <a href="/facts/Aragonese_language/hduBfPCR">Aragonese</a>, <a href="/facts/Walloon_language/Tdp6gx6D">Walloon</a>, <a href="/facts/Piedmontese_language/LfB3fUCH">Piedmontese</a>, <a href="/facts/Lombard_language/lTY3EwFz">Lombard</a>, <a href="/facts/Neapolitan_language/Y941BtNT">Neapolitan</a>, <a href="/facts/Sicilian_language/RQHklfV4">Sicilian</a>, <a href="/facts/Emilian-Romagnol_language/sGY8QS4P">Emilian-Romagnol</a>, <a href="/facts/Ligurian_language/4yCLAl5e">Ligurian</a>, <a href="/facts/Ladin_language/uXJQIv3Q">Ladin</a></td></tr><tr><td><a href="/facts/Celtic_languages/edRrGrMF">Celtic</a></td><td><a href="/facts/Proto-Celtic_language/RLla8fIB">Proto-Celtic</a></td><td>Once spoken across Europe, but now mostly confined to its northwestern edge.</td><td><a href="/facts/Gaulish/CAQo48pc">Gaulish</a>, <a href="/facts/Celtiberian_language/wvfcvTLH">Lepontic</a>, <a href="/facts/Noric_language/MtS8tPvf">Noric</a>, <a href="/facts/Pictish/PM5zpEkM">Pictish</a>, <a href="/facts/Cumbric/unDG8K3c">Cumbric</a>, <a href="/facts/Old_Irish_language/79xpaDv5">Old Irish</a>, <a href="/facts/Middle_Welsh_language/l7rvzqc1">Middle Welsh</a>, <a href="/facts/Gallaecian_language/eYyhEYUt">Gallaecian</a>, <a href="/facts/Galatian_language/aSLQjvrp">Galatian</a></td><td><a href="/facts/Irish_language/Kw97s2l4">Irish</a>, <a href="/facts/Scottish_Gaelic/KMI4MmzJ">Scottish Gaelic</a>, <a href="/facts/Welsh_language/4Pz8r6yk">Welsh</a>, <a href="/facts/Breton_language/e0Rpgyvf">Breton</a>, <a href="/facts/Cornish_language/DtPyMKHv">Cornish</a>, <a href="/facts/Manx_language/lG7JMRr0">Manx</a></td></tr><tr><td><a href="/facts/Germanic_languages/BxAJX3Kf">Germanic</a></td><td><a href="/facts/Proto-Germanic_language/LJrKRx5A">Proto-Germanic</a></td><td>Branched into three subfamilies: <a href="/facts/West_Germanic_languages/PbeIH9Jz">West Germanic</a>, <a href="/facts/East_Germanic_languages/b2XRVS0b">East Germanic</a> (now extinct), and <a href="/facts/North_Germanic_languages/zocYfWp8">North Germanic</a>.</td><td><a href="/facts/Old_English/9rsmQG2a">Old English</a>, <a href="/facts/Old_Norse/3dIvgsm5">Old Norse</a>, <a href="/facts/Gothic_language/14Hrn0o2">Gothic</a>, <a href="/facts/Old_High_German/Vr3YC8sW">Old High German</a>, <a href="/facts/Old_Saxon/9DDedJAM">Old Saxon</a>, <a href="/facts/Vandalic_language/2MwsIoHv">Vandalic</a>, <a href="/facts/Burgundian_language_(Germanic)/7gNzAbbS">Burgundian</a>, <a href="/facts/Crimean_Gothic/40vr7pmX">Crimean Gothic</a>, <a href="/facts/Norn_language/Rf0HFld5">Norn</a>, <a href="/facts/Greenlandic_Norse/jxTWMu43">Greenlandic Norse</a></td><td><a href="/facts/English_language/tpkxGt7b">English</a>, <a href="/facts/German_language/oWaQIDA8">German</a>, <a href="/facts/Afrikaans/jYqEPHmA">Afrikaans</a>, <a href="/facts/Dutch_language/yIB5lbsx">Dutch</a>, <a href="/facts/Yiddish/VfmsR6pW">Yiddish</a>, <a href="/facts/Norwegian_language/TGEyeerM">Norwegian</a>, <a href="/facts/Danish_language/sTcGXTMJ">Danish</a>, <a href="/facts/Swedish_language/1DkSIXkH">Swedish</a>, <a href="/facts/Frisian_languages/vEAn7PrD">Frisian</a>, <a href="/facts/Icelandic_language/4GmzhaoT">Icelandic</a>, <a href="/facts/Faroese_language/1nf145FG">Faroese</a>, <a href="/facts/Luxembourgish_language/HsVzn2YA">Luxembourgish</a>, <a href="/facts/Scots_language/0qPof8oC">Scots</a>, <a href="/facts/Limburgish/5mS23Txg">Limburgish</a>, <a href="/facts/Wymysorys_language/5tUN6SHb">Wymysorys</a>, <a href="/facts/Elfdalian/bK3hKUgG">Elfdalian</a></td></tr><tr><td><a href="/facts/Balto-Slavic_languages/1tgXUIgu">Balto-Slavic</a></td><td><a href="/facts/Proto-Balto-Slavic_language/wE6x9r0c">Proto-Balto-Slavic</a></td><td>Branched into the <a href="/facts/Baltic_languages/Jmj2ckcI">Baltic languages</a> and the <a href="/facts/Slavic_languages/b5GaeFx1">Slavic languages</a>.</td><td><a href="/facts/Old_Prussian/FKlDSyfc">Old Prussian</a>, <a href="/facts/Old_Church_Slavonic/KCEH4cFL">Old Church Slavonic</a>, <a href="/facts/Sudovian_language/kQF5nzKh">Sudovian</a>, <a href="/facts/Semigallian_language/nPY8u1NS">Semigallian</a>, <a href="/facts/Selonian_language/fEQMaUoY">Selonian</a>, <a href="/facts/Skalvian_language/qu26g01y">Skalvian</a>, <a href="/facts/Galindian_language/WvCtYSQs">Galindian</a>, <a href="/facts/Polabian_language/WqykA7Qz">Polabian</a>, <a href="/facts/Knaanic_language/4aJwFu1a">Knaanic</a></td><td>Baltic: <a href="/facts/Latvian_language/1LRCJorI">Latvian</a>, <a href="/facts/Latgalian_language/FpVXCT93">Latgalian</a> and <a href="/facts/Lithuanian_language/p0bS9M0R">Lithuanian</a>;Slavic: <a href="/facts/Russian_language/ETXrTgHV">Russian</a>, <a href="/facts/Ukrainian_language/2zDw7rpD">Ukrainian</a>, <a href="/facts/Belarusian_language/yRuE1cfX">Belarusian</a>, <a href="/facts/Polish_language/lzpvYDvV">Polish</a>, <a href="/facts/Czech_language/ySvEftdh">Czech</a>, <a href="/facts/Slovak_language/HmmobnJ8">Slovak</a>, <a href="/facts/Sorbian_languages/0amEJgBM">Sorbian</a>, <a href="/facts/Serbo-Croatian/MS85Xuwk">Serbo-Croatian</a>, <a href="/facts/Bulgarian_language/susG15pr">Bulgarian</a>, <a href="/facts/Slovenian_language/09YPyUQr">Slovenian</a>, <a href="/facts/Macedonian_language/FdnWMYBR">Macedonian</a>, <a href="/facts/Kashubian_language/gs64oDQe">Kashubian</a>, <a href="/facts/Rusyn_language/T1XYCasx">Rusyn</a></td></tr><tr><td><a href="/facts/Indo-Iranian_languages/uIfMNTQV">Indo-Iranian</a></td><td><a href="/facts/Proto-Indo-Iranian_language/EElV5HNY">Proto-Indo-Iranian</a></td><td>Branched into the <a href="/facts/Indo-Aryan_languages/hm2N7fYp">Indo-Aryan</a>, <a href="/facts/Iranian_languages/JaJyqM4t">Iranian</a> and <a href="/facts/Nuristani_languages/J5eoKQEW">Nuristani</a> languages.</td><td><a href="/facts/Vedic_Sanskrit/V0fnIRdc">Vedic Sanskrit</a>, <a href="/facts/Pali_language/HLQW2fvS">Pali</a>, <a href="/facts/Prakrit/8X8AUK2y">Prakrit languages</a>; <a href="/facts/Old_Persian/gxx47Ul7">Old Persian</a>, <a href="/facts/Parthian_language/ky9xW3Vk">Parthian</a>, <a href="/facts/Old_Azeri/ghp09o6E">Old Azeri</a>, <a href="/facts/Median_language/MNvb2VUr">Median</a>, <a href="/facts/Elu/LGEKA3SE">Elu</a>, <a href="/facts/Sogdian_language/yMPGFtBu">Sogdian</a>, <a href="/facts/Saka_language/mWXlJ7R0">Saka</a>, <a href="/facts/Avestan_language/0b7tvGQs">Avestan</a>, <a href="/facts/Bactrian_language/gM8bVKwJ">Bactrian</a></td><td>Indo-Aryan: <a href="/facts/Hindustani_language/rPnbEyYP">Hindustani</a> (<a href="/facts/Hindi/n1QIEeCC">Hindi</a> and <a href="/facts/Urdu/oLrhuXc6">Urdu</a>), <a href="/facts/Marathi_language/uIJuwlFW">Marathi</a>, <a href="/facts/Sylheti_language/dNAe8qmy">Sylheti</a>, <a href="/facts/Bengali_language/twpKobqA">Bengali</a>, <a href="/facts/Assamese_language/rS7BqK0P">Assamese</a>, <a href="/facts/Odia_language/RCSkWVSf">Odia</a>, <a href="/facts/Konkani_language/mjEpS7Ly">Konkani</a>, <a href="/facts/Gujarati_language/kGKRRbwe">Gujarati</a>, <a href="/facts/Nepali_language/TSC8VdAw">Nepali</a>, <a href="/facts/Dogri_language/NcrAy4QH">Dogri</a>, <a href="/facts/Romani_language/NouAKyrh">Romani</a>, <a href="/facts/Sindhi_language/fQFk8mVz">Sindhi</a>, <a href="/facts/Maithili_language/Wg2btkFY">Maithili</a>, <a href="/facts/Sinhala_language/qfPUFGYS">Sinhala</a>, <a href="/facts/Dhivehi_language/ld63l0V9">Dhivehi</a>, <a href="/facts/Punjabi_language/Dps9vRRe">Punjabi</a>, <a href="/facts/Kashmiri_language/b35X0L3H">Kashmiri</a>, <a href="/facts/Sanskrit/ychfjhlx">Sanskrit</a> (<a href="/facts/Revived_language/PMocdBYs">revived</a>);Iranian: <a href="/facts/Persian_language/jfUYbHbt">Persian</a>, <a href="/facts/Pashto/hc2ndCqx">Pashto</a>, <a href="/facts/Balochi_language/w88uLrxl">Balochi</a>, <a href="/facts/Kurdish_languages/6LSckYAz">Kurdish</a>, <a href="/facts/Zaza_language/arqKp6CQ">Zaza</a>, <a href="/facts/Ossetian_language/a4MHjCtL">Ossetian</a>, <a href="/facts/Luri_language/eMUvd40S">Luri</a>, <a href="/facts/Talysh_language/dPyfvL8x">Talyshi</a>, <a href="/facts/Tati_language_(Iran)/B3JAIf96">Tati</a>, <a href="/facts/Gilaki_language/IrKIqy44">Gilaki</a>, <a href="/facts/Mazanderani_language/gkWdr7b3">Mazandarani</a>, <a href="/facts/Semnani_language/mlyyygaw">Semnani</a>, <a href="/facts/Yaghnobi_language/5fjBegsJ">Yaghnobi</a>;Nuristani: <a href="/facts/Kat%C3%AB_language/Aj9Qvtbt">Katë</a>, <a href="/facts/Prasun_language/RaneFnzL">Prasun</a>, <a href="/facts/Ashkun_language/wmbPhJQX">Ashkun</a>, <a href="/facts/Nuristani_Kalasha_language/WUWmMWb5">Nuristani Kalasha</a>, <a href="/facts/Tregami_language/Jds11tw7">Tregami</a>, <a href="/facts/Zemiaki_language/ckH8u6Eq">Zemiaki</a></td></tr><tr><td><a href="/facts/Armenian_language/tELuE2wG">Armenian</a></td><td><a href="/facts/Proto-Armenian_language/dnooySy1">Proto-Armenian</a></td><td>Branched into <a href="/facts/Eastern_Armenian/qvxWtyD1">Eastern Armenian</a> and <a href="/facts/Western_Armenian/TlFLQIPF">Western Armenian</a>.</td><td><a href="/facts/Classical_Armenian/3uY0hIAW">Classical Armenian</a></td><td><a href="/facts/Armenian_language/tELuE2wG">Armenian</a></td></tr><tr><td><a href="/facts/Hellenic_languages/8968kKo7">Hellenic</a></td><td><a href="/facts/Proto-Greek_language/0KW6sWxy">Proto-Greek</a></td><td>Modern Greek and Tsakonian are the only surviving varieties of Greek.</td><td><a href="/facts/Ancient_Greek/LIK7NlUh">Ancient Greek</a>, <a href="/facts/Ancient_Macedonian_language/724e1XxN">Ancient Macedonian</a></td><td><a href="/facts/Greek_language/pzDd6eIz">Greek</a>, <a href="/facts/Tsakonian_language/s3a6THHp">Tsakonian</a></td></tr><tr><td><a href="/facts/Albanian_language/6CyC8GPJ">Albanian</a></td><td><a href="/facts/Proto-Albanian_language/qpEFdDLG">Proto-Albanian</a></td><td>Albanian is the only surviving representative of the <a href="/facts/Albanoid/vBc6mHwF">Albanoid</a> branch of the Indo-European language family.<a class="footnote-ref" id="fnref:33" href="#fn:33">33</a><a class="footnote-ref" id="fnref:34" href="#fn:34">34</a></td><td><a href="/facts/Illyrian_language/VIsJzVb5">Illyrian</a> (disputed); <a href="/facts/Daco-Thracian/hTefsLIB">Daco-Thracian</a> (disputed)</td><td><a href="/facts/Albanian_language/6CyC8GPJ">Albanian</a> (<a href="/facts/Gheg_Albanian/PdW1BC7d">Gheg</a> and <a href="/facts/Tosk_Albanian/N5YD5rrL">Tosk</a>)</td></tr></tbody></table>
Commonly proposed subgroups of Indo-European languages include <a href="/facts/Italo-Celtic/gU6JsBN9">Italo-Celtic</a>, <a href="/facts/Graeco-Aryan/6qYEycvr">Graeco-Aryan</a>, <a href="/facts/Graeco-Armenian/G7aYTq0a">Graeco-Armenian</a>, <a href="/facts/Graeco-Phrygian/oLI1jy69">Graeco-Phrygian</a>, <a href="/facts/Daco-Thracian/hTefsLIB">Daco-Thracian</a>, and <a href="/facts/Thraco-Illyrian/lyLbpUHL">Thraco-Illyrian</a>.
There are numerous lexical similarities between the Proto-Indo-European and <a href="/facts/Proto-Kartvelian_language/EKttVBfs">Proto-Kartvelian</a> languages due to early <a href="/facts/Language_contact/xU290Qnk">language contact</a>, as well as some morphological similarities—notably the <a href="/facts/Indo-European_ablaut/fphzPyba">Indo-European ablaut</a>, which is remarkably similar to the root ablaut system reconstructible for Proto-Kartvelian.<a class="footnote-ref" id="fnref:35" href="#fn:35">35</a><a class="footnote-ref" id="fnref:36" href="#fn:36">36</a>

<h3>Marginally attested languages</h3>
The <a href="/facts/Lusitanian_language/l4Sg6BQK">Lusitanian language</a> was a marginally attested language spoken in areas near the border between present-day <a href="/facts/Portugal/lYzwDQ63">Portugal</a> and <a href="/facts/Spain/bIyrB8EY">Spain</a>.
The <a href="/facts/Venetic_language/MLyQhcry">Venetic</a> and <a href="/facts/Liburnian_language/20ByETXY">Liburnian</a> languages known from the North Adriatic region are sometimes classified as Italic.
Albanian and Greek are the only surviving Indo-European descendants of a <a href="/facts/Paleo-Balkan_languages/Lq6NJYb2">Paleo-Balkan</a> language area, named for their occurrence in or in the vicinity of the <a href="/facts/Balkan_peninsula/5Hy8ly0d">Balkan peninsula</a>. Most of the other languages of this area—including <a href="/facts/Illyrian_languages/VIsJzVb5">Illyrian</a>, <a href="/facts/Thracian_language/XmboM1mC">Thracian</a>, and <a href="/facts/Dacian_language/vaShLLqH">Dacian</a>—do not appear to be members of any other subfamilies of PIE, but are so poorly attested that proper classification of them is not possible. Forming an exception, <a href="/facts/Phrygian_language/aDE5TWF6">Phrygian</a> is sufficiently well-attested to allow proposals of a particularly close affiliation with Greek, and a <a href="/facts/Graeco-Phrygian/oLI1jy69">Graeco-Phrygian</a> branch of Indo-European is becoming increasingly accepted.<a class="footnote-ref" id="fnref:37" href="#fn:37">37</a><a class="footnote-ref" id="fnref:38" href="#fn:38">38</a><a class="footnote-ref" id="fnref:39" href="#fn:39">39</a>

<h2 id="phonology">Phonology</h2>
Main article: <a href="/facts/Proto-Indo-European_phonology/NyBduMX6">Proto-Indo-European phonology</a>
Proto-Indo-European <a href="/facts/Phonology/qWAsvnok">phonology</a> has been reconstructed in some detail. Notable features of the most widely accepted (but not uncontroversial) reconstruction include:

<ul><li>three series of <a href="/facts/Stop_consonant/okC9pztc">stop consonants</a> reconstructed as <a href="/facts/Voiceless_consonant/575TtTUn">voiceless</a>, <a href="/facts/Voiced_consonant/VdqrEGQ3">voiced</a>, and <a href="/facts/Breathy_voice/ynD4GYNn">breathy voiced</a>;</li>
<li><a href="/facts/Sonorant/D1kkuEby">sonorant</a> consonants that could be used <a href="/facts/Syllabic_consonant/J19Uh6EK">syllabically</a>;</li>
<li>three so-called <a href="/facts/Laryngeal_theory/WzwJPK3U">laryngeal</a> consonants, whose exact pronunciation is not well-established but which are believed to have existed in part based on their detectable effects on adjacent sounds;</li>
<li>the <a href="/facts/Fricative/1FQuuhfX">fricative</a> /s/</li>
<li>a <a href="/facts/Vowel/BNhCeFtH">vowel</a> system in which /e/ and /o/ were the most frequently occurring vowels. The existence of /a/ as a separate phoneme is debated.</li></ul>
<h3>Notation</h3>
<h4>Vowels</h4>
The vowels in commonly used notation are:<a class="footnote-ref" id="fnref:40" href="#fn:40">40</a>

<table><tbody><tr><th>Type</th><th><a href="/facts/Vowel_length/BhBqJJu3">length</a></th><th><a href="/facts/Front_vowel/htKQs3AT">front</a></th><th><a href="/facts/Back_vowel/gyHoGCH0">back</a></th></tr><tr><th rowspan="2"><a href="/facts/Close-mid_vowel/rK07wQEd">Mid</a></th><th>short</th><td>*<a href="/facts/Close-mid_front_unrounded_vowel/e9YNLF97">e</a></td><td>*<a href="/facts/Close-mid_back_rounded_vowel/VwS9cKWJ">o</a></td></tr><tr><th>long</th><td>*<a href="/facts/Close-mid_front_unrounded_vowel/e9YNLF97">ē</a></td><td>*<a href="/facts/Close-mid_back_rounded_vowel/VwS9cKWJ">ō</a></td></tr></tbody></table>
<h4>Consonants</h4>
The corresponding consonants in commonly used notation are:<a class="footnote-ref" id="fnref:41" href="#fn:41">41</a><a class="footnote-ref" id="fnref:42" href="#fn:42">42</a>

<table><tbody><tr><th rowspan="2" colspan="2">Type</th><th rowspan="2"><a href="/facts/Labial_consonant/bv4MqTMf">Labial</a></th><th rowspan="2"><a href="/facts/Coronal_consonant/nJA2jL4n">Coronal</a></th><th colspan="3"><a href="/facts/Dorsal_consonant/mene9hFt">Dorsal</a></th><th colspan="3"><a href="/facts/Laryngeal_theory/WzwJPK3U">Laryngeal</a></th><th rowspan="6"></th></tr><tr><th><a href="/facts/Palatalization_(phonetics)/LXAIp4TB">palatal</a></th><th><a href="/facts/Velar_consonant/blWClp79">plain</a></th><th><a href="/facts/Labialized_velar_consonant/VVUIqtF0">labial</a></th><th><a href="/facts/Glottal_consonant/rMdEdLxH">glottal</a></th><th colspan="2"><a href="/facts/Velar_consonant/blWClp79">velar</a> or <a href="/facts/Uvular_consonant/XA5mSSKK">uvular</a></th></tr><tr><th colspan="2"><a href="/facts/Nasal_consonant/m6D3cVhe">Nasals</a></th><td>*m /<a href="/facts/Voiced_bilabial_nasal/1pd7NK2x">m</a>/</td><td>*n /<a href="/facts/Voiced_alveolar_nasal/0CEs8314">n</a>/</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><th rowspan="3"><a href="/facts/Stop_consonant/okC9pztc">Stops</a></th><th><a href="/facts/Voicelessness/575TtTUn">voiceless</a></th><td>*p /<a href="/facts/Voiceless_bilabial_plosive/w4M9Igp6">p</a>/</td><td>*t /<a href="/facts/Voiceless_alveolar_plosive/1GaDe2Vy">t</a>/</td><td>*ḱ /<a href="/facts/Palatalization_(phonetics)/LXAIp4TB">kʲ</a>/</td><td>*k /<a href="/facts/Voiceless_velar_plosive/dDppVb6e">k</a>/</td><td>*kʷ /<a href="/facts/Labialization/gxgAWAQI">kʷ</a>/</td><td></td><td></td><td></td></tr><tr><th><a href="/facts/Voice_(phonetics)/VdqrEGQ3">voiced</a></th><td>(*b) /<a href="/facts/Voiced_bilabial_plosive/6ReC9arR">b</a>/</td><td>*d /<a href="/facts/Voiced_alveolar_plosive/A6hNvmCp">d</a>/</td><td>*ǵ /<a href="/facts/Palatalization_(phonetics)/LXAIp4TB">ɡʲ</a>/</td><td>*g /<a href="/facts/Voiced_velar_plosive/f6udTvfQ">ɡ</a>/</td><td>*gʷ /<a href="/facts/Labialization/gxgAWAQI">ɡʷ</a>/</td><td></td><td></td><td></td></tr><tr><th><a href="/facts/Breathy_voice/ynD4GYNn">aspirated</a></th><td>*bʰ /<a href="/facts/Breathy_voice/ynD4GYNn">bʱ</a>/</td><td>*dʰ /<a href="/facts/Breathy_voice/ynD4GYNn">dʱ</a>/</td><td>*ǵʰ /<a href="/facts/Palatalization_(phonetics)/LXAIp4TB">ɡʲʱ</a>/</td><td>*gʰ /<a href="/facts/Breathy_voice/ynD4GYNn">ɡʱ</a>/</td><td>*gʷʰ /<a href="/facts/Labialization/gxgAWAQI">ɡʷʱ</a>/</td><td></td><td></td><td></td></tr><tr><th colspan="2" rowspan="2"><a href="/facts/Fricative_consonant/1FQuuhfX">Fricatives</a></th><td rowspan="2"></td><td rowspan="2">*s /<a href="/facts/Voiceless_alveolar_fricative/WLKtEYDe">s</a>/</td><td rowspan="2"></td><td rowspan="2"></td><td rowspan="2"></td><td>*h₁ /<a href="/facts/Voiceless_glottal_fricative/lfRB7CPW">h</a>/~/<a href="/facts/Glottal_stop/Xfqy2ArP">ʔ</a>/</td><td>*h₂ /<a href="/facts/Voiceless_velar_fricative/mrKPhobk">x</a>/~/<a href="/facts/Voiceless_uvular_plosive/aKeHjs1N">qː</a>/</td><td>*h₃ /<a href="/facts/Labialization/gxgAWAQI">ɣʷ</a>/~/<a href="/facts/Labialization/gxgAWAQI">qʷː</a>/</td><th>Laryngeal Pronunciation(<a href="/facts/Jens_Elmeg%C3%A5rd_Rasmussen/U5FD5bPt">J. E. Rasmussen</a>, <a href="/facts/Alwin_Kloekhorst/tVG78TCT">Kloekhorst</a>)</th></tr><tr><td>[<a href="/facts/Mid_central_vowel/CCx0wYy3">ə</a>]</td><td>[<a href="/facts/Near-open_central_vowel/GUR9Nk56">ɐ</a>]</td><td>[<a href="/facts/Close-mid_central_rounded_vowel/A2kLVUnz">ɵ</a>]</td><th><a href="/facts/Syllabic_consonant/J19Uh6EK">Syllabic</a> <a href="/facts/Allophone/2gp1p5PN">allophone</a></th></tr><tr><th rowspan="2"><a href="/facts/Liquid_consonant/NLaIlh7R">Liquids</a></th><th><a href="/facts/Trill_consonant/GKS3ga4q">Trill</a></th><td></td><td>*r /<a href="/facts/Voiced_alveolar_trill/rDplJobc">r</a>/</td><td></td><td></td><td></td><td></td><td></td><td></td><th rowspan="3"></th></tr><tr><th><a href="/facts/Lateral_consonant/Mcyc1or8">Lateral</a></th><td></td><td>*l /<a href="/facts/Voiced_alveolar_lateral_approximant/dgbHhqeK">l</a>/</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><th colspan="2" rowspan="2"><a href="/facts/Semivowels/9nPDkQdw">Semivowels</a></th><td rowspan="2"></td><td rowspan="2"></td><td>*y /<a href="/facts/Voiced_palatal_approximant/v0NVCbUh">j</a>/</td><td rowspan="2"></td><td>*w /<a href="/facts/Voiced_labial%E2%80%93velar_approximant/HLDqbrvr">w</a>/</td><td rowspan="2"></td><td rowspan="2"></td><td rowspan="2"></td></tr><tr><td>*i [<a href="/facts/Close_front_unrounded_vowel/rSUdlCPU">i</a>]</td><td>*u [<a href="/facts/Close_back_rounded_vowel/gqlQLfse">u</a>]</td><th>Syllabic allophone<a class="footnote-ref" id="fnref:43" href="#fn:43">43</a></th></tr></tbody></table>
All <a href="/facts/Sonorant/D1kkuEby">sonorants</a> (i.e. nasals, liquids and semivowels) can appear in <a href="/facts/Syllabic_consonant/J19Uh6EK">syllabic</a> position. The syllabic allophones of *y and *w are realized as the surface vowels *i and *u respectively.<a class="footnote-ref" id="fnref:44" href="#fn:44">44</a>

<h3>Accent</h3>
The <a href="/facts/Proto-Indo-European_accent/WThQgHxK">Proto-Indo-European accent</a> is reconstructed today as having had variable lexical stress, which could appear on any syllable and whose position often varied among different members of a paradigm (e.g. between singular and plural of a verbal paradigm). Stressed syllables received a higher pitch; therefore it is often said that PIE had a <a href="/facts/Pitch-accent_language/aIQu5zse">pitch accent</a>. The location of the stress is associated with ablaut variations, especially between full-grade vowels (/e/ and /o/) and zero-grade (i.e. lack of a vowel), but not entirely predictable from it.
The accent is best preserved in <a href="/facts/Vedic_Sanskrit/V0fnIRdc">Vedic Sanskrit</a> and (in the case of nouns) <a href="/facts/Ancient_Greek/LIK7NlUh">Ancient Greek</a>, and indirectly attested in a number of phenomena in other IE languages, such as <a href="/facts/Verner%27s_Law/zT7ylWGn">Verner's Law</a> in the Germanic branch. Sources for Indo-European accentuation are also the <a href="/facts/Balto-Slavic_languages/1tgXUIgu">Balto-Slavic</a> accentual system and plene spelling in <a href="/facts/Hittite_language/Pc8YGhRU">Hittite</a> cuneiform. To account for mismatches between the accent of Vedic Sanskrit and Ancient Greek, as well as a few other phenomena, a few historical linguists prefer to reconstruct PIE as a <a href="/facts/Tone_(linguistics)/eprhXrWJ">tone language</a> where each <a href="/facts/Morpheme/4JNcPMHs">morpheme</a> had an inherent tone; the sequence of tones in a word then evolved, according to that hypothesis, into the placement of lexical stress in different ways in different IE branches.<a class="footnote-ref" id="fnref:45" href="#fn:45">45</a>

<h2 id="morphology">Morphology</h2>
Proto-Indo-European, like its earliest attested descendants, was a highly inflected, <a href="/facts/Fusional_language/VHVxrPAv">fusional language</a>. Suffixation and ablaut were the main methods of marking inflection, both for nominals and verbs. The subject of a sentence was in the nominative case and agreed in number and person with the verb, which was additionally marked for voice, tense, aspect, and mood.<a class="footnote-ref" id="fnref:46" href="#fn:46">46</a>

<h3>Root</h3>
Main article: <a href="/facts/Proto-Indo-European_root/L3p63vYW">Proto-Indo-European root</a>
Proto-Indo-European nominals and verbs were primarily composed of roots – <a href="/facts/Affix/MKeAIE7e">affix</a>-lacking <a href="/facts/Morpheme/4JNcPMHs">morphemes</a> that carried the core <a href="/facts/Lexical_(semiotics)/EV2rqeBx">lexical</a> meaning of a word. They were used to derive related words (cf. the English root "-friend-", from which are derived related words such as friendship, friendly, befriend, and newly coined words such as unfriend). As a rule, roots were monosyllabic, and had the structure (s)(C)CVC(C), where the symbols C stand for consonants, V stands for a variable vowel, and optional components are in parentheses. All roots ended in a consonant and, although less certain, they appear to have started with a consonant as well.<a class="footnote-ref" id="fnref:47" href="#fn:47">47</a>
A root plus a <a href="/facts/Suffix/Nlnft3NK">suffix</a> formed a <a href="/facts/Word_stem/7Aq8G5fP">word stem</a>, and a word stem plus an <a href="/facts/Suffix/Nlnft3NK">inflectional ending</a> formed a word. Proto-Indo-European was a <a href="/facts/Fusional_language/VHVxrPAv">fusional language</a>, in which <a href="/facts/Inflection/mhXSXpmJ">inflectional</a> morphemes signaled the grammatical relationships between words. This dependence on inflectional morphemes means that roots in PIE, unlike those in English, were rarely used without affixes.<a class="footnote-ref" id="fnref:48" href="#fn:48">48</a>

<h3>Ablaut</h3>
Main article: <a href="/facts/Indo-European_ablaut/fphzPyba">Indo-European ablaut</a>
Many morphemes in Proto-Indo-European had short e as their inherent vowel; the <a href="/facts/Indo-European_ablaut/fphzPyba">Indo-European ablaut</a> is the change of this short e to short o, long e (ē), long o (ō), or no vowel. The forms are referred to as the "ablaut grades" of the morpheme—the e-grade, o-grade, zero-grade (no vowel), etc. This variation in vowels occurred both within <a href="/facts/Inflectional_morphology/mhXSXpmJ">inflectional morphology</a> (e.g., different grammatical forms of a noun or verb may have different vowels) and <a href="/facts/Derivational_morphology/1ED86Ao8">derivational morphology</a> (e.g., a verb and an associated abstract <a href="/facts/Verbal_noun/6BXSFywx">verbal noun</a> may have different vowels).<a class="footnote-ref" id="fnref:49" href="#fn:49">49</a>
Categories that PIE distinguished through ablaut were often also identifiable by contrasting endings, but the loss of these endings in some later Indo-European languages has led them to use ablaut alone to identify grammatical categories, as in the Modern English words sing, sang, sung.

<h3>Noun</h3>
<a href="/facts/Proto-Indo-European_nominals/PDSxdQ0u">Proto-Indo-European nouns</a> were probably declined for eight or nine cases:<a class="footnote-ref" id="fnref:50" href="#fn:50">50</a>

<ul><li><a href="/facts/Nominative_case/wXX3Vn4x">nominative</a>: marks the <a href="/facts/Subject_(grammar)/h5M1cQJ2">subject</a> of a verb. Words that follow a linking verb (<a href="/facts/Copulative_verb/nFkAhQhL">copulative verb</a>) and restate the subject of that verb also use the nominative case. The nominative is the dictionary form of the noun.</li>
<li><a href="/facts/Accusative_case/HA1Q81qd">accusative</a>: used for the <a href="/facts/Direct_object/wybTVzna">direct object</a> of a <a href="/facts/Transitive_verb/3TtAs9FH">transitive verb</a>.</li>
<li><a href="/facts/Genitive_case/nMXh3StK">genitive</a>: marks a <a href="/facts/Noun/SsnDNfkX">noun</a> as modifying another noun.</li>
<li><a href="/facts/Dative_case/bBjY0RVf">dative</a>: used to indicate the indirect object of a transitive verb, such as Jacob in Maria gave Jacob a drink.</li>
<li><a href="/facts/Instrumental_case/NvGhAHWa">instrumental</a>: marks the instrument or means by, or with, which the subject achieves or accomplishes an action. It may be either a physical object or an abstract concept.</li>
<li><a href="/facts/Ablative_case/GotGMD3k">ablative</a>: used to express motion away from something.</li>
<li><a href="/facts/Locative_case/h9KCqqhq">locative</a>: expresses location, corresponding vaguely to the English prepositions in, on, at, and by.</li>
<li><a href="/facts/Vocative_case/xKY0N2tb">vocative</a>: used for a word that identifies an addressee. A <a href="/facts/Vocative_expression/bQYgxL7r">vocative expression</a> is one of direct address where the identity of the party spoken to is set forth expressly within a sentence. For example, in the sentence, "I don't know, John", John is a vocative expression that indicates the party being addressed.</li>
<li><a href="/facts/Allative_case/xc9PKo26">allative</a>: used as a type of <a href="/facts/Locative_case/h9KCqqhq">locative case</a> that expresses movement towards something. It was preserved in Anatolian (particularly Old Hittite), and fossilized traces of it have been found in Greek. It is also present in Tocharian.<a class="footnote-ref" id="fnref:51" href="#fn:51">51</a> Its PIE shape is uncertain, with candidates including *-h2(e), *-(e)h2, or *-a.<a class="footnote-ref" id="fnref:52" href="#fn:52">52</a></li></ul>
Late Proto-Indo-European had three <a href="/facts/Grammatical_gender/2hEshpnP">grammatical genders</a>:

<ul><li>masculine</li>
<li>feminine</li>
<li>neuter</li></ul>
This system is probably derived from an older two-gender system, attested in Anatolian languages: <a href="/facts/Common_gender/2hEshpnP">common</a> (or <a href="/facts/Animate_gender/mr4xbcdG">animate</a>) and neuter (or inanimate) gender. The feminine gender only arose in the later period of the language.<a class="footnote-ref" id="fnref:53" href="#fn:53">53</a> Neuter nouns collapsed the nominative, vocative and accusative into a single form, the plural of which used a special <a href="/facts/Collective_noun/0HDhzEQG">collective</a> suffix *-h2 (manifested in most descendants as -a). This same collective suffix in extended forms *-eh2 and *-ih2 (respectively on thematic and athematic nouns, becoming -ā and -ī in the early daughter languages) became used to form feminine nouns from masculines.
All nominals distinguished three <a href="/facts/Grammatical_number/zzs5AV6v">numbers</a>:

<ul><li>singular</li>
<li>dual</li>
<li>plural</li></ul>
These numbers were also distinguished in verbs (see below), requiring <a href="/facts/Agreement_(linguistics)/MxF9ErBV">agreement</a> with their subject nominal.

<h3>Pronoun</h3>
<a href="/facts/Proto-Indo-European_pronouns/cQqpuJdb">Proto-Indo-European pronouns</a> are difficult to reconstruct, owing to their variety in later languages. PIE had personal <a href="/facts/Pronoun/UsbSNRSl">pronouns</a> in the first and second <a href="/facts/Grammatical_person/PfUA43oU">grammatical person</a>, but not the third person, where <a href="/facts/Demonstrative_pronoun/XAM9dxwK">demonstrative pronouns</a> were used instead. The personal pronouns had their own unique forms and endings, and some had <a href="/facts/Suppletion/Teoa2AGI">two distinct stems</a>; this is most obvious in the first person singular where the two stems are still preserved in English I and me. There were also two varieties for the accusative, genitive and dative cases, a stressed and an <a href="/facts/Enclitic/4A00CTek">enclitic</a> form.<a class="footnote-ref" id="fnref:54" href="#fn:54">54</a>

Personal pronouns<a class="footnote-ref" id="fnref:55" href="#fn:55">55</a><table><tbody><tr><th rowspan="2">Case</th><th colspan="2">First person</th><th colspan="2">Second person</th></tr><tr><th>Singular</th><th>Plural</th><th>Singular</th><th>Plural</th></tr><tr><th><a href="/facts/Nominative_case/wXX3Vn4x">Nominative</a></th><td>*h₁eǵ(oH/Hom)</td><td>*wei</td><td>*tuH</td><td>*yuH</td></tr><tr><th><a href="/facts/Accusative_case/HA1Q81qd">Accusative</a></th><td>*h₁mé, *h₁me</td><td>*n̥smé, *nōs</td><td>*twé</td><td>*usmé, *wōs</td></tr><tr><th><a href="/facts/Genitive_case/nMXh3StK">Genitive</a></th><td>*h₁méne, *h₁moi</td><td>*n̥s(er)o-, *nos</td><td>*tewe, *toi</td><td>*yus(er)o-, *wos</td></tr><tr><th><a href="/facts/Dative_case/bBjY0RVf">Dative</a></th><td>*h₁méǵʰio, *h₁moi</td><td>*n̥smei, *n̥s</td><td>*tébʰio, *toi</td><td>*usmei</td></tr><tr><th><a href="/facts/Instrumental_case/NvGhAHWa">Instrumental</a></th><td>*h₁moí</td><td>*n̥smoí</td><td>*toí</td><td>*usmoí</td></tr><tr><th><a href="/facts/Ablative_case/GotGMD3k">Ablative</a></th><td>*h₁med</td><td>*n̥smed</td><td>*tued</td><td>*usmed</td></tr><tr><th><a href="/facts/Locative_case/h9KCqqhq">Locative</a></th><td>*h₁moí</td><td>*n̥smi</td><td>*toí</td><td>*usmi</td></tr></tbody></table>
<h3>Verb</h3>
<a href="/facts/Proto-Indo-European_verbs/Gf0vLd6B">Proto-Indo-European verbs</a>, like the nouns, exhibited an ablaut system.
The most basic categorisation for the reconstructed Indo-European verb is <a href="/facts/Grammatical_aspect/zX9gFXn9">grammatical aspect</a>. Verbs are classed as:

<ul><li><a href="/facts/Stative_verb/8GglTfgx">stative</a>: verbs that depict a state of being</li>
<li><a href="/facts/Imperfective_aspect/PX3wkfcb">imperfective</a>: verbs depicting ongoing, habitual or repeated action</li>
<li><a href="/facts/Perfective_aspect/Me4egTFk">perfective</a>: verbs depicting a completed action or actions viewed as an entire process.</li></ul>
Verbs have at least four <a href="/facts/Grammatical_mood/QS8qwCPm">grammatical moods</a>:

<ul><li><a href="/facts/Indicative_mood/kR0xlIKJ">indicative</a>: indicates that something is a statement of fact; in other words, to express what the speaker considers to be a known state of affairs, as in <a href="/facts/Declarative_sentence/GhKKkcm2">declarative sentences</a>.</li>
<li><a href="/facts/Imperative_mood/E3zRtPgJ">imperative</a>: forms commands or requests, including the giving of prohibition or permission, or any other kind of advice or exhortation.</li>
<li><a href="/facts/Subjunctive_mood/r71oa4sE">subjunctive</a>: used to express various states of unreality such as wish, emotion, possibility, judgment, opinion, obligation, or action that has not yet occurred</li>
<li><a href="/facts/Optative_mood/j1mN6wnD">optative</a>: indicates a wish or hope. It is similar to the <a href="/facts/Cohortative_mood/dgDJYpHT">cohortative mood</a> and is closely related to the <a href="/facts/Subjunctive_mood/r71oa4sE">subjunctive mood</a>.</li></ul>
Verbs had two <a href="/facts/Grammatical_voice/KGxB8PER">grammatical voices</a>:

<ul><li><a href="/facts/Active_voice/JlJ4yevg">active</a>: used in a clause whose subject expresses the main verb's <a href="/facts/Agent_(grammar)/EyraFmNd">agent</a>.</li>
<li><a href="/facts/Mediopassive_voice/XbjNujAs">mediopassive</a>: for the <a href="/facts/Middle_voice/KGxB8PER">middle voice</a> and the <a href="/facts/Passive_voice/9lpHvV33">passive voice</a>.</li></ul>
Verbs had three <a href="/facts/Grammatical_person/PfUA43oU">grammatical persons</a>: first, second and third.
Verbs had three <a href="/facts/Grammatical_number/zzs5AV6v">grammatical numbers</a>:

<ul><li>singular</li>
<li><a href="/facts/Dual_grammatical_number/DGIb0rhs">dual</a>: referring to precisely two of the entities (objects or persons) identified by the noun or pronoun.</li>
<li><a href="/facts/Plural/3VjXP7VF">plural</a>: a number other than singular or dual.</li></ul>
Verbs were probably marked by a highly developed system of <a href="/facts/Participle/rYxXQKaG">participles</a>, one for each combination of tense and voice, and an assorted array of <a href="/facts/Verbal_noun/6BXSFywx">verbal nouns</a> and adjectival formations.
The following table shows a possible reconstruction of the PIE verb endings from Sihler, which largely represents the current consensus among Indo-Europeanists.

<table><tbody><tr><th colspan="2" rowspan="2">Person</th><th colspan="2">Sihler (1995)<a class="footnote-ref" id="fnref:56" href="#fn:56">56</a></th></tr><tr><th><a href="/facts/Athematic_stem/e2hdURAH">Athematic</a></th><th><a href="/facts/Thematic_stem/e2hdURAH">Thematic</a></th></tr><tr><th rowspan="3"><a href="/facts/Grammatical_number/zzs5AV6v">Singular</a></th><th><a href="/facts/Grammatical_person/PfUA43oU">1st</a></th><td>*-mi</td><td>*-oh₂</td></tr><tr><th>2nd</th><td>*-si</td><td>*-esi</td></tr><tr><th>3rd</th><td>*-ti</td><td>*-eti</td></tr><tr><th rowspan="3">Dual</th><th>1st</th><td>*-wos</td><td>*-owos</td></tr><tr><th>2nd</th><td>*-th₁es</td><td>*-eth₁es</td></tr><tr><th>3rd</th><td>*-tes</td><td>*-etes</td></tr><tr><th rowspan="3">Plural</th><th>1st</th><td>*-mos</td><td>*-omos</td></tr><tr><th>2nd</th><td>*-te</td><td>*-ete</td></tr><tr><th>3rd</th><td>*-nti</td><td>*-onti</td></tr></tbody></table>
<h3>Numbers</h3>
<a href="/facts/Proto-Indo-European_numerals/e0jcojEd">Proto-Indo-European numerals</a> are generally reconstructed as follows:

<table><tbody><tr><th>Number</th><th>Sihler<a class="footnote-ref" id="fnref:57" href="#fn:57">57</a></th></tr><tr><td>one</td><td>*(H)óynos/*(H)óywos/*(H)óyk(ʷ)os; *sḗm (full grade), *sm̥- (zero grade)</td></tr><tr><td>two</td><td>*d(u)wóh₁ (full grade), *dwi- (zero grade)</td></tr><tr><td>three</td><td>*tréyes (full grade), *tri- (zero grade)</td></tr><tr><td>four</td><td>*kʷetwóres (o-grade), *kʷ(e)twr̥- (zero grade)(see also the <a href="/facts/K%CA%B7etw%C3%B3res_rule/qclKErpd">kʷetwóres rule</a>)</td></tr><tr><td>five</td><td>*pénkʷe</td></tr><tr><td>six</td><td>*s(w)éḱs; originally perhaps *wéḱs, with *s- under the influence of *septḿ̥</td></tr><tr><td>seven</td><td>*septḿ̥</td></tr><tr><td>eight</td><td>*oḱtṓ(w) or *h₃eḱtṓ(w)</td></tr><tr><td>nine</td><td>*h₁néwn̥</td></tr><tr><td>ten</td><td>*déḱm̥(t)</td></tr></tbody></table>
Rather than specifically 100, *ḱm̥tóm may originally have meant "a large number".<a class="footnote-ref" id="fnref:58" href="#fn:58">58</a>

<h3>Particle</h3>
<a href="/facts/Proto-Indo-European_particles/QIBB2BX0">Proto-Indo-European particles</a> were probably used both as <a href="/facts/Adverb/gDhqt9np">adverbs</a> and as <a href="/facts/Preposition_and_postposition/Bhz0tAMI">postpositions</a>. These postpositions became prepositions in most daughter languages.
Reconstructed particles include for example, *upo "under, below"; the <a href="/facts/Affirmative_and_negative/JMkpne01">negators</a> *ne, *mē; the <a href="/facts/Conjunction_(grammar)/bKVVIpob">conjunctions</a> *kʷe "and", *wē "or" and others; and an <a href="/facts/Interjection/CdhKlzmB">interjection</a>, *wai!, expressing woe or agony.

<h3>Derivational morphology</h3>
Proto-Indo-European employed various means of deriving words from other words, or directly from verb roots.

<h4>Internal derivation</h4>
Internal derivation was a process that derived new words through changes in accent and ablaut alone. It was not as productive as external (affixing) derivation, but is firmly established by the evidence of various later languages.

<h5>Possessive adjectives</h5>
Possessive or associated adjectives were probably created from nouns through internal derivation. Such words could be used directly as adjectives, or they could be turned back into a noun without any change in morphology, indicating someone or something characterised by the adjective. They were probably also used as the second elements in compounds. If the first element was a noun, this created an adjective that resembled a present participle in meaning, e.g. "having much rice" or "cutting trees". When turned back into nouns, such compounds were <a href="/facts/Bahuvrihi/yPhD4z8q">Bahuvrihis</a> or semantically resembled <a href="/facts/Agent_noun/8cK4TWaM">agent nouns</a>.
In thematic stems, creating a possessive adjective seems to have involved shifting the accent one syllable to the right, for example:<a class="footnote-ref" id="fnref:59" href="#fn:59">59</a>

<ul><li>*tómh₁-o-s "slice" (Greek tómos) > *tomh₁-ó-s "cutting" (i.e. "making slices"; Greek tomós) > *dr-u-tomh₁-ó-s "cutting trees" (Greek drutómos "woodcutter" with irregular accent).</li>
<li>*wólh₁-o-s "wish" (Sanskrit vára-) > *wolh₁-ó-s "having wishes" (Sanskrit vará- "suitor").</li></ul>
In athematic stems, there was a change in the accent/ablaut class. The reconstructed four classes followed an ordering in which a derivation would shift the class one to the right:<a class="footnote-ref" id="fnref:60" href="#fn:60">60</a>

acrostatic → proterokinetic → hysterokinetic → amphikinetic
The reason for this particular ordering of the classes in derivation is not known. Some examples:

<ul><li>Acrostatic *krót-u-s ~ *krét-u-s "strength" (Sanskrit krátu-) > proterokinetic *krét-u-s ~ *kr̥t-éw-s "having strength, strong" (Greek kratús).</li>
<li>Hysterokinetic *ph₂-tḗr ~ *ph₂-tr-és "father" (Greek patḗr) > amphikinetic *h₁su-péh₂-tōr ~ *h₁su-ph₂-tr-és "having a good father" (Greek εὑπάτωρ, eupátōr).</li></ul>
<h5>Vrddhi</h5>
A <a href="/facts/Vrddhi/TpsI5W8V">vrddhi</a> derivation, named after the Sanskrit grammatical term, signifying "of, belonging to, descended from". It was characterised by "upgrading" the root grade, from zero to full (e) or from full to lengthened (ē). When upgrading from zero to full grade, the vowel could sometimes be inserted in the "wrong" place, creating a different stem from the original full grade.
Examples:<a class="footnote-ref" id="fnref:61" href="#fn:61">61</a>

<ul><li>full grade *swéḱuro-s "father-in-law" (<a href="/facts/Vedic_Sanskrit/V0fnIRdc">Vedic Sanskrit</a> śváśura-) > lengthened grade *swēḱuró-s "relating to one's father-in-law" (Vedic śvāśura-, <a href="/facts/Old_High_German/Vr3YC8sW">Old High German</a> swāgur "brother-in-law").</li>
<li>full grade *dyḗw-s > zero grade *diw-és "sky" > new full grade *deyw-o-s "god, <a href="/facts/Dyeus/IHeMWbCV">sky god</a>" (Vedic devás, <a href="/facts/Latin/pM3Kge85">Latin</a> deus, etc.). Note the difference in vowel placement, *dyew- in the full-grade stem of the original noun, but *deyw- in the vrddhi derivative.</li></ul>
<h5>Nominalization</h5>
Adjectives with accent on the thematic vowel could be turned into nouns by moving the accent back onto the root. A zero grade root could remain so, or be "upgraded" to full grade like in a vrddhi derivative. Some examples:<a class="footnote-ref" id="fnref:62" href="#fn:62">62</a>

<ul><li>PIE *ǵn̥h₁-tó-s "born" (Vedic jātá-) > *ǵénh₁-to- "thing that is born" (German Kind).</li>
<li>Greek leukós "white" > leũkos "a kind of fish", literally "white one".</li>
<li>Vedic kṛṣṇá- "dark" > kṛ́ṣṇa- "dark one", also "antelope".</li></ul>
This kind of derivation is likely related to the possessive adjectives, and can be seen as essentially the reverse of it.

<h4>Affixal derivation</h4>

<h2 id="syntax">Syntax</h2>
The <a href="/facts/Syntax/6PxSV98p">syntax</a> of the older Indo-European languages has been studied in earnest since at least the late nineteenth century, by such scholars as <a href="/facts/Hermann_Hirt/K1VNzFhj">Hermann Hirt</a> and <a href="/facts/Berthold_Delbr%C3%BCck/2ek8Xkox">Berthold Delbrück</a>. In the second half of the twentieth century, interest in the topic increased and led to reconstructions of Proto-Indo-European syntax.<a class="footnote-ref" id="fnref:63" href="#fn:63">63</a>
Since all the early attested IE languages were inflectional, PIE is thought to have relied primarily on morphological markers, rather than <a href="/facts/Word_order/nXtB9Gm2">word order</a>, to signal <a href="/facts/Syntax/6PxSV98p">syntactic</a> relationships within sentences.<a class="footnote-ref" id="fnref:64" href="#fn:64">64</a> Still, a default (<a href="/facts/Markedness/vofcEvg6">unmarked</a>) word order is thought to have existed in PIE. In 1892, <a href="/facts/Jacob_Wackernagel/5t91Wkd9">Jacob Wackernagel</a> reconstructed PIE's word order as <a href="/facts/Subject%E2%80%93verb%E2%80%93object/N0DS8deK">subject–verb–object</a> (SVO), based on evidence in Vedic Sanskrit.<a class="footnote-ref" id="fnref:65" href="#fn:65">65</a>
<a href="/facts/Winfred_P._Lehmann/lFhxn5xV">Winfred P. Lehmann</a> (1974), on the other hand, reconstructs PIE as a <a href="/facts/Subject%E2%80%93object%E2%80%93verb/yqAybkWr">subject–object–verb</a> (SOV) language. He posits that the presence of <a href="/facts/Grammatical_person/PfUA43oU">person marking</a> in PIE verbs motivated a shift from OV to VO order in later dialects. Many of the descendant languages have VO order: modern Greek, <a href="/facts/Romance_languages/TMK4KHI3">Romance</a> and <a href="/facts/Albanian_language/6CyC8GPJ">Albanian</a> prefer SVO, <a href="/facts/Insular_Celtic/GxWCv26A">Insular Celtic</a> has VSO as the default order, and even the <a href="/facts/Anatolian_languages/aGWvRmue">Anatolian languages</a> show some signs of this word order shift. <a href="/facts/Tocharian_languages/zCILXC6E">Tocharian</a> and <a href="/facts/Indo-Iranian_languages/uIfMNTQV">Indo-Iranian</a>, meanwhile, retained the conservative OV order. Lehmann attributes the context-dependent order preferences in Baltic, Slavic and Germanic to outside influences.<a class="footnote-ref" id="fnref:66" href="#fn:66">66</a> <a href="/facts/Donald_Ringe/JEbCgYFQ">Donald Ringe</a> (2006), however, attributes these to internal developments instead.<a class="footnote-ref" id="fnref:67" href="#fn:67">67</a>
<a href="/facts/Paul_Friedrich_(linguist)/JCF0rKKh">Paul Friedrich</a> (1975) disagrees with Lehmann's analysis. He reconstructs PIE with the following syntax:

<ul><li>basic SVO word order</li>
<li>adjectives before nouns</li>
<li>head nouns before <a href="/facts/Genitive/nMXh3StK">genitives</a></li>
<li><a href="/facts/Prepositions/Bhz0tAMI">prepositions</a> rather than postpositions</li>
<li>no dominant order in <a href="/facts/Comparison_(grammar)/he1zw790">comparative constructions</a></li>
<li>main clauses before <a href="/facts/Relative_clauses/zFSPHLwE">relative clauses</a></li></ul>
Friedrich notes that even among those Indo-European languages with basic OV word order, none of them are rigidly OV. He also notes that these non-rigid OV languages mainly occur in parts of the IE area that overlap with OV languages from other families (such as <a href="/facts/Uralic/4K0r9XRI">Uralic</a> and <a href="/facts/Dravidian_languages/s8pMU64e">Dravidian</a>), whereas VO is predominant in the central parts of the IE area. For these reasons, among others, he argues for a VO common ancestor.<a class="footnote-ref" id="fnref:68" href="#fn:68">68</a>
<a href="/facts/Hans_Henrich_Hock/FYwt6DPT">Hans Henrich Hock</a> (2015) reports that the SVO hypothesis still has some adherents, but the "broad consensus" among PIE scholars is that PIE would have been an SOV language.<a class="footnote-ref" id="fnref:69" href="#fn:69">69</a> The SOV default word order with other orders used to express emphasis (e.g., <a href="/facts/Verb%E2%80%93subject%E2%80%93object/uYtjUPIh">verb–subject–object</a> to emphasise the verb) is attested in <a href="/facts/Old_Indo-Aryan/hm2N7fYp">Old Indo-Aryan</a>, <a href="/facts/Old_Iranian/JaJyqM4t">Old Iranian</a>, <a href="/facts/Old_Latin/HU7I4za6">Old Latin</a> and <a href="/facts/Hittite_language/Pc8YGhRU">Hittite</a>, while traces of it can be found in the <a href="/facts/Enclitic/4A00CTek">enclitic</a> personal pronouns of the <a href="/facts/Tocharian_languages/zCILXC6E">Tocharian languages</a>.<a class="footnote-ref" id="fnref:70" href="#fn:70">70</a>

<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Indo-European_vocabulary/I60Js0zP">Indo-European vocabulary</a></li>
<li><a href="/facts/Proto-Indo-European_verbs/Gf0vLd6B">Proto-Indo-European verbs</a></li>
<li><a href="/facts/Proto-Indo-European_pronouns/cQqpuJdb">Proto-Indo-European pronouns</a></li>
<li><a href="/facts/List_of_Indo-European_languages/Yl8BJAap">List of Indo-European languages</a></li>
<li><a href="/facts/Indo-European_sound_laws/09wNuAGu">Indo-European sound laws</a></li>
<li><a href="/facts/List_of_proto-languages/bhGWsArb">List of proto-languages</a></li></ul>
<h2 id="notes">Notes</h2>

<h2 id="bibliography">Bibliography</h2>

<ul><li>Anthony, David W.; Ringe, Don (2015). <a href="https://doi.org/10.1146%2Fannurev-linguist-030514-124812">"The Indo-European Homeland from Linguistic and Archaeological Perspectives"</a>. Annual Review of Linguistics. 1 (1): 199–219. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1146%2Fannurev-linguist-030514-124812">10.1146/annurev-linguist-030514-124812</a>.</li>
<li>Bomhard, Allan (2019). <a href="https://www.academia.edu/40002289">"The Origins of Proto-Indo-European: The Caucasian Substrate Hypothesis"</a>. Journal of Indo-European Studies. 47 (1–2).</li>
<li>Clackson, James (18 October 2007). <a href="https://www.cambridge.org/core/product/identifier/9780511808616/type/book">Indo-European Linguistics: An Introduction</a>. Cambridge University Press. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1017%2Fcbo9780511808616">10.1017/cbo9780511808616</a>. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-521-65367-1.</li>
<li>Fortson, Benjamin W. (2010). Indo-European language and culture: an introduction (2nd ed.). Malden, MA: Blackwell. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-405-18896-8.</li>
<li>Kapović, Mate (2017). "Proto-Indo-European phonology". In Kapović, Mate (ed.). The Indo-European Languages (2nd ed.). London: Routledge. pp. 13–60. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-415-73062-4.</li>
<li>Mallory, J. P. (1989). <a href="https://archive.org/details/insearchofindoeu00jpma">In Search of the Indo-Europeans: Language, Archaeology, and Myth</a>. Thames & Hudson. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-500-05052-1.</li>
<li><a href="/facts/J._P._Mallory/AguhYRaq">Mallory, J. P.</a>; <a href="/facts/Douglas_Q._Adams/5nh1lmK4">Adams, D. Q.</a> (2006), The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World, <a href="/facts/Oxford_University_Press/CYyTzzWG">Oxford University Press</a>, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-199-29668-2</li>
<li><a href="/facts/Meier-Br%C3%BCgger/bv0ARHrX">Meier-Brügger, Michael</a> (2003), Indo-European Linguistics, New York: De Gruyter, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 3-110-17433-2</li>
<li>Szemerenyi, Oswald J. L. (13 February 1997). <a href="https://academic.oup.com/book/48334">Introduction to Indo-European Linguistics</a>. Oxford University Press. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1093%2Foso%2F9780198240150.001.0001">10.1093/oso/9780198240150.001.0001</a>. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-383-01320-7.</li>
<li>Kümmel, Martin Joachim (2022). <a href="https://www.italian-journal-linguistics.com/app/uploads/2021/05/9_Kuemmel.pdf">"Voiceless high vowels and syncope in older Indo-European"</a> (PDF). Italian Journal of Linguistics. 32 (1): 175–190. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.26346%2F1120-2726-153">10.26346/1120-2726-153</a>.</li>
<li>Kümmel, Martin Joachim. <a href="https://archive.org/download/kummelljubljana2019.pdf_202011/k%C3%BCmmelljubljana2019.pdf.pdf">"Uvular Stops or a Glottal Fricative? Theory and Data in Recent Reconstructions of PIE "Laryngeals""</a> (PDF). Seminar für Indogermanistik.</li>
<li>Klein, Jared; Joseph, Brian; Fritz, Matthias, eds. (25 September 2017), Handbook of Comparative and Historical Indo-European Linguistics, vol. 1, De Gruyter Mouton, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1515%2F9783110261288">10.1515/9783110261288</a>, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-110-26128-8</li>
<li>Klein, Jared; Joseph, Brian; Fritz, Matthias, eds. (23 October 2017), "Handbook of Comparative and Historical Indo-European Linguistics: An International Handbook", Handbook of Comparative and Historical Indo-European Linguistics, vol. 2, De Gruyter Mouton, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1515%2F9783110523874">10.1515/9783110523874</a>, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-110-52387-4</li>
<li>Klein, Jared; Joseph, Brian; Fritz, Matthias, eds. (11 June 2018), Handbook of Comparative and Historical Indo-European Linguistics, vol. 3, De Gruyter Mouton, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1515%2F9783110542431">10.1515/9783110542431</a>, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-110-54243-1</li>
<li>Strazny, Philipp, ed. (2000), Dictionary of Historical and Comparative Linguistics, Routledge, <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-1-579-58218-0</li></ul>

<h2 id="external-links">External links</h2>

Look up Appendix:Proto-Indo-European Swadesh list in Wiktionary, the free dictionary.

<ul><li>At the University of Texas Linguistic Research Center: <a href="http://liberalarts.utexas.edu/lrc/resources/books/index.php">List of online books</a> <a href="https://web.archive.org/web/20170728215921/http://liberalarts.utexas.edu/lrc/resources/books/index.php">Archived</a> 28 July 2017 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a>, <a href="https://lrc.la.utexas.edu/lex">Indo-European Lexicon</a></li>
<li><a href="http://pielexicon.hum.helsinki.fi/">Proto-Indo-European Lexicon</a> at the University of Helsinki, Department of Modern Languages, Department of World Cultures, Indo-European Studies</li>
<li><a href="https://archive.org/details/kummeleaa2019.pdf">"Wheel and chariot in early IE: What exactly can we conclude from the linguistic data?"</a> (PDF). Martin Joachim Kümmel, department of Indo-European linguistics, <a href="/facts/University_of_Jena/Kv3JXbEL">University of Jena</a>.</li>
<li><a href="http://ielex.mpi.nl/">Indo-European Lexical Cognacy Database</a> <a href="https://web.archive.org/web/20151107054612/http://ielex.mpi.nl/">Archived</a> 7 November 2015 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li>
<li><a href="https://spw.uni-goettingen.de/projects/aig/index.html">glottothèque – Ancient Indo-European Grammars online</a>, an online collection of video lectures on Ancient Indo-European languages</li></ul>

<h2 id="references">References</h2>

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<li id="fn:2">"Archaeology et al: an Indo-European study" (PDF). School of History, Classics and Archaeology. The University of Edinburgh. 11 April 2018. Retrieved 1 December 2018. <a href="https://www.ed.ac.uk/files/atoms/files/archaeology_et_al_-_an_indo-european_study.pdf" target="_blank">https://www.ed.ac.uk/files/atoms/files/archaeology_et_al_-_an_indo-european_study.pdf</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
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<li id="fn:4">Powell, Eric A. "Telling Tales in Proto-Indo-European". Archaeology. Retrieved 30 July 2017. <a href="http://www.archaeology.org/exclusives/articles/1302-proto-indo-european-schleichers-fable" target="_blank">http://www.archaeology.org/exclusives/articles/1302-proto-indo-european-schleichers-fable</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">Fortson (2010), p. 16. - Fortson, Benjamin W. (2010). Indo-European language and culture: an introduction (2nd ed.). Malden, MA: Blackwell. ISBN 978-1-405-18896-8. <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
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<li id="fn:8">"Sir William Jones, British orientalist and jurist". Encyclopædia Britannica. Retrieved 3 September 2016. <a href="https://www.britannica.com/biography/William-Jones-British-orientalist-and-jurist" target="_blank">https://www.britannica.com/biography/William-Jones-British-orientalist-and-jurist</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">Auroux, Sylvain (2000). History of the Language Sciences. Walter de Gruyter. p. 1156. ISBN 3-11-016735-2. <a href="3-11-016735-2" target="_blank">3-11-016735-2</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">Blench, Roger (2004). "Archaeology and language: Methods and issues". In Bintliff, J. (ed.). A Companion to Archaeology (PDF). Oxford, UK: Basil Blackwell. pp. 52–74. <a href="/wiki/Roger_Blench" target="_blank">/wiki/Roger_Blench</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">Wheeler, Kip. "The Sanskrit Connection: Keeping Up With the Joneses". Carson–Newman University. Retrieved 16 April 2013. <a href="http://web.cn.edu/kwheeler/IE_Main4_Sanskrit.html" target="_blank">http://web.cn.edu/kwheeler/IE_Main4_Sanskrit.html</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">Momma, Haruko (2013). From Philology to English Studies: Language and Culture in the Nineteenth Century. Cambridge University Press. pp. 65–66. ISBN 978-0-521-51886-4. <a href="978-0-521-51886-4" target="_blank">978-0-521-51886-4</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">"Franz Bopp, German philologist". Encyclopædia Britannica. Retrieved 26 August 2016. <a href="https://www.britannica.com/biography/Franz-Bopp" target="_blank">https://www.britannica.com/biography/Franz-Bopp</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">"Grimm's law, linguistics". Encyclopædia Britannica. Retrieved 26 August 2016. <a href="https://www.britannica.com/topic/Grimms-law" target="_blank">https://www.britannica.com/topic/Grimms-law</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
<li id="fn:15">"Neogrammarian, German scholar". Encyclopædia Britannica. Retrieved 26 August 2016. <a href="https://www.britannica.com/science/Neogrammarian" target="_blank">https://www.britannica.com/science/Neogrammarian</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">"August Schleicher, German linguist". Encyclopædia Britannica. Retrieved 26 August 2016. <a href="https://www.britannica.com/biography/August-Schleicher" target="_blank">https://www.britannica.com/biography/August-Schleicher</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">Saussure, Ferdinand de (1879). Mémoire sur le système primitif des voyelles dans les langues indo-européennes. University of California Libraries. Leipsick : B. G. Teubner. <a href="http://archive.org/details/memoiresurlesyst00saus" target="_blank">http://archive.org/details/memoiresurlesyst00saus</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">Kuryłowicz, Jerzy (1927). "ə indo-européen et ḫ hittite". In: Witold Taszycki and Witold Doroszewki (eds.), Symbolae Grammaticae in honorem Ioannis Rozwadowski, v. 1, 95–104. Krakow: Uniwersytet Jagielloński. <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
<li id="fn:19">Mallory & Adams 2006, pp. 3, 5, 135, 209–210. - Mallory, J. P.; Adams, D. Q. (2006), The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World, Oxford University Press, ISBN 978-0-199-29668-2 <a href="#fnref:19" class="footnote-back-ref">↩</a></li>
<li id="fn:20">See:
Bomhard: "This scenario is supported not only by linguistic evidence, but also by a growing body of archeological and genetic evidence. The Indo-Europeans have been identified with several cultural complexes existing in that area between 4,500—3,500 BCE. The literature supporting such a homeland is both extensive and persuasive [...]. Consequently, other scenarios regarding the possible Indo-European homeland, such as Anatolia, have now been mostly abandoned."[20]
Anthony & Ringe: "Archaeological evidence and linguistic evidence converge in support of an origin of Indo-European languages on the Pontic-Caspian steppes around 4,000 years BCE. The evidence is so strong that arguments in support of other hypotheses should be reexamined."[21]
Mallory: "The Kurgan solution is attractive and has been accepted by many archaeologists and linguists, in part or total. It is the solution one encounters in the Encyclopædia Britannica and the Grand Dictionnaire Encyclopédique Larousse."[22]
Strazny: "The single most popular proposal is the Pontic steppes (see the Kurgan hypothesis)..."[23]
 <a href="#fnref:20" class="footnote-back-ref">↩</a></li>
<li id="fn:21">Anthony, David W. (2007). The horse, the wheel, and language: how bronze-age riders from the Eurasian steppes shaped the modern world (8th reprint ed.). Princeton, N.J.: Princeton University Press. ISBN 978-0-691-05887-0. <a href="978-0-691-05887-0" target="_blank">978-0-691-05887-0</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></li>
<li id="fn:22">Balter, Michael (13 February 2015). "Mysterious Indo-European homeland may have been in the steppes of Ukraine and Russia". Science. doi:10.1126/science.aaa7858. Retrieved 17 February 2015. <a href="https://www.science.org/content/article/mysterious-indo-european-homeland-may-have-been-steppes-ukraine-and-russia" target="_blank">https://www.science.org/content/article/mysterious-indo-european-homeland-may-have-been-steppes-ukraine-and-russia</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></li>
<li id="fn:23">Balter, Michael (13 February 2015). "Mysterious Indo-European homeland may have been in the steppes of Ukraine and Russia". Science. doi:10.1126/science.aaa7858. Retrieved 17 February 2015. <a href="https://www.science.org/content/article/mysterious-indo-european-homeland-may-have-been-steppes-ukraine-and-russia" target="_blank">https://www.science.org/content/article/mysterious-indo-european-homeland-may-have-been-steppes-ukraine-and-russia</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></li>
<li id="fn:24">Gimbutas, Marija (1985). "Primary and Secondary Homeland of the Indo-Europeans: comments on Gamkrelidze-Ivanov articles". Journal of Indo-European Studies. 13 (1–2): 185–202. <a href="#fnref:24" class="footnote-back-ref">↩</a></li>
<li id="fn:25">Bouckaert, Remco; Lemey, P.; Dunn, M.; Greenhill, S. J.; Alekseyenko, A. V.; Drummond, A. J.; Gray, R. D.; Suchard, M. A.; et al. (24 August 2012), "Mapping the Origins and Expansion of the Indo-European Language Family" (PDF), Science, 337 (6097): 957–960, Bibcode:2012Sci...337..957B, doi:10.1126/science.1219669, hdl:11858/00-001M-0000-000F-EADF-A, PMC 4112997, PMID 22923579 <a href="http://pubman.mpdl.mpg.de/pubman/item/escidoc:1539154/component/escidoc:1539165/Bouckaert_2012.pdf" target="_blank">http://pubman.mpdl.mpg.de/pubman/item/escidoc:1539154/component/escidoc:1539165/Bouckaert_2012.pdf</a> <a href="#fnref:25" class="footnote-back-ref">↩</a></li>
<li id="fn:26">Chang, Will; Cathcart, Chundra; Hall, David; Garrett, Andrew (2015). "Ancestry-constrained phylogenetic analysis supports the Indo-European steppe hypothesis". Language. 91 (1): 194–244. doi:10.1353/lan.2015.0005. ISSN 1535-0665. S2CID 143978664. <a href="https://muse.jhu.edu/content/crossref/journals/language/v091/91.1.chang.html" target="_blank">https://muse.jhu.edu/content/crossref/journals/language/v091/91.1.chang.html</a> <a href="#fnref:26" class="footnote-back-ref">↩</a></li>
<li id="fn:27">Thapar, Romila (2006). India: Historical Beginnings and the Concept of the Aryan. National Book Trust. p. 127. ISBN 9788123747798. <a href="/wiki/Romila_Thapar" target="_blank">/wiki/Romila_Thapar</a> <a href="#fnref:27" class="footnote-back-ref">↩</a></li>
<li id="fn:28">"The opposing argument, that speakers of Indo-European languages were indigenous to the Indian subcontinent, is not supported by any reliable scholarship". Doniger, Wendy (2017). "Another Great Story" Archived 14 May 2023 at the Wayback Machine", review of Asko Parpola's The Roots of Hinduism. In: Inference, International Review of Science, Volume 3, Issue 2. <a href="/wiki/Wendy_Doniger" target="_blank">/wiki/Wendy_Doniger</a> <a href="#fnref:28" class="footnote-back-ref">↩</a></li>
<li id="fn:29">Mallory, J. P. (2006). The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World. Douglas Q. Adams. New York: Oxford University Press. ISBN 978-1-4294-7104-6. OCLC 139999117. <a href="978-1-4294-7104-6" target="_blank">978-1-4294-7104-6</a> <a href="#fnref:29" class="footnote-back-ref">↩</a></li>
<li id="fn:30">Renfrew, Colin (2017) "Marija Redivia : DNA and Indo-European origins" (The Oriental Institute lecture series : Marija Gimbutas memorial lecture, Chicago. November 8, 2017). <a href="https://www.youtube.com/watch?v=pmv3J55bdZc" target="_blank">https://www.youtube.com/watch?v=pmv3J55bdZc</a> <a href="#fnref:30" class="footnote-back-ref">↩</a></li>
<li id="fn:31">Pellard, Thomas; Sagart, Laurent; Jacques, Guillaume (2018). "L'indo-européen n'est pas un mythe". Bulletin de la Société de Linguistique de Paris. 113 (1): 79–102. doi:10.2143/BSL.113.1.3285465. S2CID 171874630. <a href="/wiki/Laurent_Sagart" target="_blank">/wiki/Laurent_Sagart</a> <a href="#fnref:31" class="footnote-back-ref">↩</a></li>
<li id="fn:32">Mallory & Adams 2006, p. 14. - Mallory, J. P.; Adams, D. Q. (2006), The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World, Oxford University Press, ISBN 978-0-199-29668-2 <a href="#fnref:32" class="footnote-back-ref">↩</a></li>
<li id="fn:33">Trumper, John (2018). "Some Celto-Albanian isoglosses and their implications". In Grimaldi, Mirko; Lai, Rosangela; Franco, Ludovico; Baldi, Benedetta (eds.). Structuring Variation in Romance Linguistics and Beyond: In Honour of Leonardo M. Savoia. John Benjamins Publishing Company. ISBN 9789027263179. pp. 383–386. <a href="9789027263179" target="_blank">9789027263179</a> <a href="#fnref:33" class="footnote-back-ref">↩</a></li>
<li id="fn:34">"Perfect Phylogenetic Networks: A New Methodology for Reconstructing the Evolutionary History of Natural Languages, pg. 396" (PDF). Archived (PDF) from the original on 5 November 2010. Retrieved 22 September 2010. <a href="http://www.cs.rice.edu/~nakhleh/Papers/81.2nakhleh.pdf" target="_blank">http://www.cs.rice.edu/~nakhleh/Papers/81.2nakhleh.pdf</a> <a href="#fnref:34" class="footnote-back-ref">↩</a></li>
<li id="fn:35">Gamkrelidze, Th. & Ivanov, V. (1995). Indo-European and the Indo-Europeans: A Reconstruction and Historical Analysis of a Proto-Language and a Proto-Culture. 2 Vols. Berlin and New York: Mouton de Gruyter. <a href="#fnref:35" class="footnote-back-ref">↩</a></li>
<li id="fn:36">Gamkrelidze, T. V. (2008). Kartvelian and Indo-European: a typological comparison of reconstructed linguistic systems. Bulletin of the Georgian National Academy of Sciences 2 (2): 154–160. <a href="#fnref:36" class="footnote-back-ref">↩</a></li>
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<li id="fn:40">Kapović (2017), p. 13. - Kapović, Mate (2017). "Proto-Indo-European phonology". In Kapović, Mate (ed.). The Indo-European Languages (2nd ed.). London: Routledge. pp. 13–60. ISBN 978-0-415-73062-4. <a href="#fnref:40" class="footnote-back-ref">↩</a></li>
<li id="fn:41">Fortson (2010), §3.2. - Fortson, Benjamin W. (2010). Indo-European language and culture: an introduction (2nd ed.). Malden, MA: Blackwell. ISBN 978-1-405-18896-8. <a href="#fnref:41" class="footnote-back-ref">↩</a></li>
<li id="fn:42">Beekes (1995), §11. - Beekes, Robert (1995). Comparative Indo-European linguistics: an introduction. Amsterdam: J. Benjamins Publishing Company. pp. 147, 212–217, 233, 243. ISBN 978-1556195044. <a href="#fnref:42" class="footnote-back-ref">↩</a></li>
<li id="fn:43">Kapović (2017), p. 14. - Kapović, Mate (2017). "Proto-Indo-European phonology". In Kapović, Mate (ed.). The Indo-European Languages (2nd ed.). London: Routledge. pp. 13–60. ISBN 978-0-415-73062-4. <a href="#fnref:43" class="footnote-back-ref">↩</a></li>
<li id="fn:44">Kapović (2017), p. 14. - Kapović, Mate (2017). "Proto-Indo-European phonology". In Kapović, Mate (ed.). The Indo-European Languages (2nd ed.). London: Routledge. pp. 13–60. ISBN 978-0-415-73062-4. <a href="#fnref:44" class="footnote-back-ref">↩</a></li>
<li id="fn:45">Kortlandt, Frederik (1986). "Proto-Indo-European tones". Journal of Indo-European Studies: 153–160. S2CID 55314276. <a href="/wiki/S2CID_(identifier)" target="_blank">/wiki/S2CID_(identifier)</a> <a href="#fnref:45" class="footnote-back-ref">↩</a></li>
<li id="fn:46">Brown, Keith, ed. (2006). "Proto-Indo-European Morphology". Encyclopedia of Language and Linguistics (2nd ed.). Elsevier. ISBN 9780080547848. <a href="9780080547848" target="_blank">9780080547848</a> <a href="#fnref:46" class="footnote-back-ref">↩</a></li>
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<li id="fn:48">Fortson (2010), §4.2, §4.20. - Fortson, Benjamin W. (2010). Indo-European language and culture: an introduction (2nd ed.). Malden, MA: Blackwell. ISBN 978-1-405-18896-8. <a href="#fnref:48" class="footnote-back-ref">↩</a></li>
<li id="fn:49">Fortson (2010), pp. 73–74. - Fortson, Benjamin W. (2010). Indo-European language and culture: an introduction (2nd ed.). Malden, MA: Blackwell. ISBN 978-1-405-18896-8. <a href="#fnref:49" class="footnote-back-ref">↩</a></li>
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<li id="fn:51">Pinault, Georges-Jean (23 October 2017), "76. The morphology of Tocharian", Handbook of Comparative and Historical Indo-European Linguistics, De Gruyter Mouton, pp. 1335–1352, doi:10.1515/9783110523874-031, ISBN 978-3-11-052387-4, retrieved 8 March 2023 <a href="978-3-11-052387-4" target="_blank">978-3-11-052387-4</a> <a href="#fnref:51" class="footnote-back-ref">↩</a></li>
<li id="fn:52">Fortson (2010), pp. 102, 105. - Fortson, Benjamin W. (2010). Indo-European language and culture: an introduction (2nd ed.). Malden, MA: Blackwell. ISBN 978-1-405-18896-8. <a href="#fnref:52" class="footnote-back-ref">↩</a></li>
<li id="fn:53">Burrow, T (1955). The Sanskrit Language. Motilal Banarsidass Publ. ISBN 81-208-1767-2. <a href="81-208-1767-2" target="_blank">81-208-1767-2</a> <a href="#fnref:53" class="footnote-back-ref">↩</a></li>
<li id="fn:54">Beekes, Robert (1995). Comparative Indo-European linguistics: an introduction. Amsterdam: J. Benjamins Publishing Company. pp. 147, 212–217, 233, 243. ISBN 978-1556195044. <a href="978-1556195044" target="_blank">978-1556195044</a> <a href="#fnref:54" class="footnote-back-ref">↩</a></li>
<li id="fn:55">Beekes, Robert (1995). Comparative Indo-European linguistics: an introduction. Amsterdam: J. Benjamins Publishing Company. pp. 147, 212–217, 233, 243. ISBN 978-1556195044. <a href="978-1556195044" target="_blank">978-1556195044</a> <a href="#fnref:55" class="footnote-back-ref">↩</a></li>
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<li id="fn:58">Lehmann, Winfried P (1993), Theoretical Bases of Indo-European Linguistics, London: Routledge, pp. 252–55, ISBN 0-415-08201-3 <a href="0-415-08201-3" target="_blank">0-415-08201-3</a> <a href="#fnref:58" class="footnote-back-ref">↩</a></li>
<li id="fn:59">Jay Jasanoff. The Prehistory of the Balto-Slavic Accent. p. 21. <a href="/wiki/Jay_Jasanoff" target="_blank">/wiki/Jay_Jasanoff</a> <a href="#fnref:59" class="footnote-back-ref">↩</a></li>
<li id="fn:60">Jay Jasanoff. The Prehistory of the Balto-Slavic Accent. p. 21. <a href="/wiki/Jay_Jasanoff" target="_blank">/wiki/Jay_Jasanoff</a> <a href="#fnref:60" class="footnote-back-ref">↩</a></li>
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<li id="fn:62">Jay Jasanoff. The Prehistory of the Balto-Slavic Accent. p. 22. <a href="/wiki/Jay_Jasanoff" target="_blank">/wiki/Jay_Jasanoff</a> <a href="#fnref:62" class="footnote-back-ref">↩</a></li>
<li id="fn:63">Kulikov, Leonid; Lavidas, Nikolaos, eds. (2015). "Preface". Proto-Indo-European Syntax and its Development. John Benjamins. <a href="#fnref:63" class="footnote-back-ref">↩</a></li>
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<li id="fn:65">Hock, Hans Henrich (2015). "Proto-Indo-European verb-finality: Reconstruction, typology, validation". In Kulikov, Leonid; Lavidas, Nikolaos (eds.). Proto-Indo-European Syntax and its Development. John Benjamins. <a href="/wiki/Hans_Henrich_Hock" target="_blank">/wiki/Hans_Henrich_Hock</a> <a href="#fnref:65" class="footnote-back-ref">↩</a></li>
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<li id="fn:68">Friedrich, Paul (1975). "Proto-Indo-European Syntax". Journal of Indo-European Studies. 1 (1). University of Chicago Press. ISBN 0-941694-25-9. <a href="0-941694-25-9" target="_blank">0-941694-25-9</a> <a href="#fnref:68" class="footnote-back-ref">↩</a></li>
<li id="fn:69">Hock, Hans Henrich (2015). "Proto-Indo-European verb-finality: Reconstruction, typology, validation". In Kulikov, Leonid; Lavidas, Nikolaos (eds.). Proto-Indo-European Syntax and its Development. John Benjamins. <a href="/wiki/Hans_Henrich_Hock" target="_blank">/wiki/Hans_Henrich_Hock</a> <a href="#fnref:69" class="footnote-back-ref">↩</a></li>
<li id="fn:70">Mallory, J. P.; Adams, Douglas Q., eds. (1997). "Proto-Indo-European". Encyclopedia of Indo-European Culture. Taylor & Francis. p. 463. <a href="/wiki/Encyclopedia_of_Indo-European_Culture" target="_blank">/wiki/Encyclopedia_of_Indo-European_Culture</a> <a href="#fnref:70" class="footnote-back-ref">↩</a></li>
</ol>

Proto-Indo-European language open-in-new

Proto-Indo-European language