Old Turkic

Old Turkic (more exactly East Old Turkic, in order to distinguish from West Old Turkic) is the earliest attested form of the Common Turkic languages, first found in Second Turkic Khaganate then in Uyghur Khaganate inscriptions. In marked contrast to Middle Turkic, the geographic extent of (East) Old Turkic is rather confined, being limited mainly to East Turkistan (Old Uyghur) and Mongolia (Orkhon Turkic). In terms of the datability of extant written sources, the period of Old Turkic can be dated from slightly before 720 AD to the Mongol invasions of the 13th century. Orkhon Turkic and Old Uyghur are considered to be dialects of East Old Turkic, Orkhon Turkic being the earliest attested dialect of (East) Old Turkic. There is a difference of opinion among linguists with regard to Karakhanid Turkic (spoken in Kara-Khanid Khanate), some (among whom are Omeljan Pritsak, Sergey Malov and most importantly Marcel Erdal) classify it as another dialect of East Old Turkic, while others prefer to include Karakhanid among Middle Turkic languages; nonetheless, Karakhanid is extremely close to Old Uyghur so much so that a single grammatical description will fit both of them. East Old Turkic and West Old Turkic together comprise the Old Turkic proper. East Old Turkic is the oldest attested member of the Siberian Turkic branch of Turkic languages, and several of its now-archaic grammatical as well as lexical features are extant in the modern Yellow Uyghur, Lop Nur Uyghur and Khalaj (all of which are endangered); Khalaj, for instance, has (surprisingly) retained a considerable number of archaic Old Turkic words despite forming a language island within Central Iran and being heavily influenced by Persian. Old Uyghur is not a direct ancestor of the Modern Standard Uyghur language (also called New Uyghur); the contemporaneous ancestor of Modern Uyghur was one of the Middle Turkic languages, later giving rise to Chagatai literary language (although Modern Uyghur does retain some features of Old Uyghur whereas Chagatai almost did not influence the spoken vernacular).

Old Turkic is attested in a number of scripts, including the Old Turkic script, the Old Uyghur alphabet, the Brahmi script, and the Manichaean script. The Turkic runiform alphabet of Orkhon Turkic was deciphered by Vilhelm Thomsen in 1893.

Old Turkic often refers not to a single language, but collectively to the closely related and mutually intelligible stages of various Common Turkic languages spoken during the late first millennium.