Besides the "Nordarisch" mentioned above which was written in Brahmi, three other Iranian languages have left literary remains in Central Asia, all written in an alphabet of Aramaic origin. Two of them apparently represent the speech of south-western Persia under the Sassanids, and of north-western Persia under the Arsacids. The texts preserved in both are Manichæan but the third Iranian language, or Sogdian, has a more varied literary content and offers Buddhist, Manichæan and Christian texts, apparently in that chronological order. It was originally the language of the region round Samarkand but acquired an international character for it was used by merchants throughout the Tarim basin and spread even to China. Some Christian texts in Syriac have also been found.
The Orkhon inscriptions exhibit an old Turkish dialect written in the characters commonly called Runes and this Runic alphabet is used in manuscripts found at Tun-huang and Miran but those hitherto published are not Buddhist. But another Turkish dialect written in the Uigur alphabet, which is derived from the Syriac, was (like Sogdian) extensively used for Buddhist, Manichæan and Christian literature. The name Uigur is perhaps more correctly applied to the alphabet than the language[466] which appears to have been the literary form of the various Turkish idioms spoken north and south of the Tien-shan. The use of this dialect for Buddhist literature spread considerably when the Uigurs broke the power of Tibet in the Tarim basin about 860 and founded a kingdom themselves: it extended into China and lasted long, for Sûtras in Uigur were printed at Peking in 1330 and Uigur manuscripts copied in the reign of K'ang Hsi (1662-1723) are reported from a monastery near Suchow[467]. I am informed that a variety of this alphabet written in vertical columns is still used in some parts of Kansu where a Turkish dialect is spoken. Though Turkish was used by Buddhists in both the east and west of the Tarim basin, it appears to have been introduced into Khotan only after the Moslim conquest. Another Semitic script, hitherto unknown and found only in a fragmentary form, is believed to be the writing of the White Huns or Hephthalites.