the language of the ancient Turkic peoples of Asia. Old Turkic is represented by various records dating from the fifth to the 11th centuries, including inscriptions on tombstones of Tonyukuk, Bilgä Kagan, Kültegin, and Gudulu Kagan (written in so-called Turkic runes) and manuscripts that are Manichaean and Buddhist in content, such as The Penitential Prayer of the Manichaeans (in the Uighur alphabet).

The Old Turkic written records display many common, specific linguistic features, including the correspondence, in medial and final word position, of d/t to the sounds z/s and j of the later languages; the consonant clusters lt, rt, and nt at the juncture of a stem and an affix (usually ld, rd, and nd, respectively, in the modern languages); the dialect variations s and š ; and the accusative case form -g, -ig/-ïg.