Mongolian languages, one of three subfamilies of the Altaic language family. The Mongolian languages are spoken in Mongolia and adjacent parts of east-central Asia. Their sub classification is controversial, and no one scheme has won universal approval.
The central Mongolian languages are usually divided into a western group, consisting of the closely related Oirat (spoken in Mongolia and in the Xinjiang region of China) and Kalmyk (Russia), and an eastern group, consisting of the closely related Buryat (Russia) and Mongol (Mongolia and China) languages. Outlying languages—Moghol (spoken in Afghanistan), Daur (Inner Mongolia, China), Yellow Uighur (Gansu province, China), and the related groups of Monguor (Tu), which are spoken on the border between the provinces.
The history of the Mongolian language, both spoken and written, consists of three periods. The divisions of the spoken language are Old, or Ancient, Mongolian (through the 12th century), Middle Mongolian (13th–16th centuries), and New, or Modern, Mongolian (17th century to the present).
The Mongolian vertical script language developed at the end of the 12th century; the oldest extant text dates from roughly 1225. The Pre-Classical period of the written language corresponds to Middle Mongolian. The conversion of the Mongols to Buddhism (c. 1575) ushered in the Classical period (17th and early 18th centuries) of translation of scriptural texts from Sanskrit, Tibetan, and Chinese, and this period corresponds to the commencement of the Modern period of the spoken language.
The split between Eastern Mongolian (Khalkh, Buryat, and the dialects of Inner Mongolia) and Western Mongolian (Oirat and Kalmyk) occurred at a later stage than that between the peripheral languages and the central group. Eastern and Western groups that most contemporary linguists no longer consider the east-west split the primary division in the genealogy of the Mongolian languages.
Buryat differs from Mongol principally in its Russified vocabulary and in a few features of its phonology and morphology, most notably the change of /s/ to /h/ and the development of personal endings on the verb. The spoken languages of Inner and Outer (Khalkh) Mongolia, apart from vocabulary, likewise do not constitute distinct groupings.