Azerbaijani or Azeri (/æˈzɛəri, ɑːˈ-, əˈ-/ a(h)-ZAIR-ee, ə-), also referred to as Azerbaijani Turkic or Azerbaijani Turkish (Azərbaycan türkcəsi, آذربایجان تۆرکچهسی, Азәрбајҹан түркҹәси), is a Turkic language from the Oghuz sub-branch. It is spoken primarily by the Azerbaijani people, who live mainly in the Republic of Azerbaijan, where the North Azerbaijani variety is spoken, while Iranian Azerbaijanis in the Azerbaijan region of Iran, speak the South Azerbaijani variety. Azerbaijani is the only official language in the Republic of Azerbaijan and one of the 14 official languages of Dagestan (a federal subject of Russia), but it does not have official status in Iran, where the majority of Iranian Azerbaijani people live. Azerbaijani is also spoken to lesser varying degrees in Azerbaijani communities of Georgia and Turkey and by diaspora communities, primarily in Europe and North America.
Although there is a high degree of mutual intelligibility between both forms of Azerbaijani, there are significant differences in phonology, lexicon, morphology, syntax, and sources of loanwords. The standardized form of North Azerbaijani (spoken in the Republic of Azerbaijan and Russia) is based on the Shirvani dialect, while South Azerbaijani uses a variety of regional dialects. Since the Republic of Azerbaijan's independence from the Soviet Union in 1991, Northern Azerbaijani has used the Latin script. On the other hand, South Azerbaijani has always used and continues to use the Perso-Arabic script.
Azerbaijani is closely related to Turkmen, Turkish, Gagauz, and Qashqai, being mutually intelligible with each of these languages to varying degrees.