Oirat (Clear script: , Oirad kelen, œːrt cɛˈlən; Kalmyk: Өөрд, Őrd; Khalkha Mongolian: Ойрад, Oirad) is a Mongolic language spoken by the descendants of Oirat Mongols, now forming parts of Mongols in China, Kalmyks in Russia and Mongolians. Largely mutually intelligible to other core Central Mongolic languages, scholars differ as to whether they regard Oirat as a distinct language or a major dialect of the Mongolian language. Oirat-speaking areas are scattered across the far west of Mongolia, the northwest of China and Russia's Caspian coast, where its major variety is Kalmyk. In China, it is spoken mainly in Xinjiang, but also among the Deed Mongol of Qinghai and Subei County in Gansu.
In all three countries, Oirat has become variously endangered or even obsolescent as a direct result of government actions or as a consequence of social and economic policies. Its most widespread tribal dialect, which is spoken in all of these nations, is Torgut. The term Oirat or more precisely, Written Oirat is sometimes also used to refer to the language of historical documents written in the Clear script.
In Mongolia, there are seven historical Oirat dialects, each corresponding to a different tribe:
Dörbet is spoken in half of the districts (sums) of Uvs Province and in Dörgön sum, Khovd Province
Bayat in the sums of Malchin, Khyargas, Tes and Züüngovi, Uvs
Torgut in Bulgan sum, Khovd
Altai Uriankhai in the sums of Duut and Mönkhkhairkhan, Khovd and in the sums of Altai, Buyant and Bulgan, Bayan-Ölgii Province
Ööld in Erdenebüren, Khovd
Zakhchin in the sums of Mankhan, Altai, Üyench, Zereg and Möst, Khovd
Khoton in Tarialan, Uvs.
There are some varieties of Oirat that are difficult to classify. The Alasha dialect in Alxa League, Inner Mongolia, originally belonged to Oirat and has been classified as such by some because of its phonology. However, it has been classified by others as Mongolian proper because of its morphology. The Darkhad dialect in Mongolia's Khövsgöl Province has variously been classified as Oirat, Mongolian proper, or (less often) Buryat.