Formation of written Mongolian language is divided into three periods. It is an ancient Mongolian language, which existed in the XIII-XV centuries, the average Mongolian language – XV-XVII century, and the classic Mongolian language – xvii – beginning of xx century. Also known as "drevnemongolsky" "srednemongolsky" languages to denote the first two periods. Since the xvii century, when it created Zaya Pandit – "clear" the letter, which is also called todo Beeching, classic old written Mongolian language remained in use only in and in Inner Mongolia. "Clear" message was generated based on the language of dialectical Oirat groups, and following that appeared Oirat literary language. In Buryatia has formed a written language based on the old written Mongolian language.
And in 1931, is used based on the Latin alphabet, and in 1939 adopted a writing Cyrillic. In Inner Mongolia to date remained in the enjoyment of old written Mongolian language. In the Mongolian People's Republic of alphabet based on Cyrillic was used in 1945, this However, there were some entirely new literary languages. After the Republic ceased to be communist, old written literary language was a "second life", it became increasingly used as practice of teaching language. In today's Buryatia today also is a revival of old written Mongolian literary language. There are several classifications of the Mongolian language. If consider the classification of gd , the author shares her "real" Mongolian languages (old written language is not taken into account) in two groups: the major languages, and marginalized.