The Cyrillic letter Shcha was derived from the Glagolitic letter Shta Ⱋ ().3
The name in the Early Cyrillic alphabet was шта (šta) and is preserved in modern Bulgarian; it is pronounced штъ.
This letter was also used in Komi /t͡ʃ/ (⟨Ч⟩ was & still is used for /t͡ɕ/), which is now represented by the digraph ⟨тш⟩.
The form of the letter shcha is considered to have originated as a ligature of the letters Ш and Т.4 However in later orthographies it began to be depicted as the letter Cyrillic Sha (Ш ш) with a descender. The descender (also used in Ц) has been reinterpreted as a diacritic and used in several letters for non-Slavic languages, such as Ң and Қ.
"Cyrillic script". omniglot.com. Retrieved 2022-06-21. https://omniglot.com/writing/cyrillic.htm ↩
Maier, Ingrid (2021). "Russian Pronunciation Rules in the Alphabetum Russarum (Stockholm, Peter van Selow)". Slovo: Journal of Slavic Languages, Literatures and Cultures. 62: 39–60. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-462754 ↩
Zhang, Xiangning; Zhang, Ruolin (July 2018). "Evolution of Ancient Alphabet to Modern Greek, Latin and Cyrillic Alphabets and Transcription between Them". Proceedings of the 2018 4th International Conference on Economics, Social Science, Arts, Education and Management Engineering (ESSAEME 2018). Atlantis Press. pp. 156–162. doi:10.2991/essaeme-18.2018.30. ISBN 978-94-6252-549-8. 978-94-6252-549-8 ↩
Chodzko, Alexandre; Chodźko, Aleksander Borejko (1869). Grammaire paléoslave, suivie de textes paléoslaves (in French). [s. n.] – via Oxford University collection. https://archive.org/details/grammairepalosl00chodgoog ↩