the languages of the Mongolian peoples, which developed out of the dialects of early Mongolian (spoken by all the Mongol tribes) between the 14th and 16th centuries after the disintegration of the empire founded by Genghis Khan. The Mongolian languages comprise the northern Mongolian, synharmonic languages, including Mongolian proper, Buriat, Kalmyk, and Oirat; the southeastern, nonsynharmonic languages, including Daghur in northeastern China and Tunghsiang, Monguor, and Paoan in Tsinghai and Kansu provinces (all these languages are unwritten); and the intermediate languages—the Old Mongolian literary language and the Mogul language in Afghanistan.
Prior to the formation of a national state, the Mongols did not have a well-developed literary language and writing system that could serve as a means of written communication and preserve their cultural unity. The disintegration of the Mongol state in the 16th and 17th centuries did not result in the disappearance of Mongolian proper because it had become a literary language, serving as a means of cultural and linguistic contact between the northern and southern (or Outer and Inner) Mongols. Mongolian proper, Buriat, and Kalmyk are the best known of the Mongolian languages.
G. D. SANZHEEV