The Mongolian language (in Mongolian script: ᠮᠣᠩᠭᠣᠯ
ᠬᠡᠯᠡ Moŋɣol kele; in Mongolian Cyrillic: монгол хэл, mongol khel) is the official language of Mongolia and both the most widely-spoken and best-known member of the Mongolic language family. The number of speakers across all its dialects may be 5.2 million, including the vast majority of the residents of Mongolia and many of the Mongolian residents of the Inner Mongolia Autonomous Region. In Mongolia, the Khalkha dialect, written in Cyrillic (and at times in Latin for social networking), is predominant, while in Inner Mongolia, the language is dialectally more diverse and is written in the traditional Mongolian script. In the discussion of grammar to follow, the variety of Mongolian treated is Standard Khalkha Mongolian (i.e., the standard written language as formalized in the writing conventions and in the school grammar), but much of what is to be said is also valid for vernacular (spoken) Khalkha and for other Mongolian dialects, especially Chakhar.
Mongolian has vowel harmony and a complex syllabic structure for a Mongolic language that allows clusters of up to three consonants syllable-finally. It is a typical agglutinative language that relies on suffix chains in the verbal and nominal domains. While there is a basic word order, subject–object–predicate, ordering among noun phrases is relatively free, so grammatical roles are indicated by a system of about eight grammatical cases. There are five voices. Verbs are marked for voice, aspect, tense, and epistemic modality/evidentiality. In sentence linking, a special role is played by converbs.
Modern Mongolian evolved from Middle Mongol, the language spoken in the Mongol Empire of the 13th and 14th centuries. In the transition, a major shift in the vowel-harmony paradigm occurred, long vowels developed, the case system changed slightly, and the verbal system was restructured. Mongolian is related to the extinct Khitan language. It was believed that Mongolian is related to Turkic, Tungusic, Korean and Japonic languages but this view is now seen as obsolete. These languages have been grouped under the now discredited Altaic language family and contrasted with the Mainland Southeast Asia linguistic area. Mongolian literature is well attested in written form from the 13th century but has earlier Mongolic precursors in the literature of the Khitan and other Xianbei peoples. The Inscription of Hüis Tolgoi dated to 630 CE is currently the oldest substantial Mongolic or Para-Mongolic text discovered.
Mongolian is the official national language of Mongolia, where it is spoken (but not written) by nearly 3.6 million people (2014 estimate), and the official provincial language (both spoken and written forms) of Inner Mongolia, China, where there are at least 4.1 million ethnic Mongols. Across the whole of China, the language is spoken by roughly half of the country's 5.8 million ethnic Mongols (2005 estimate) However, the exact number of Mongolian speakers in China is unknown, as there is no data available on the language proficiency of that country's citizens. The use of Mongolian in Inner Mongolia, has witnessed periods of decline and revival over the last few hundred years. The language experienced a decline during the late Qing period, a revival between 1947 and 1965, a second decline between 1966 and 1976, a second revival between 1977 and 1992, and a third decline between 1995 and 2012. However, in spite of the decline of the Mongolian language in some of Inner Mongolia's urban areas and educational spheres, the ethnic identity of the urbanized Chinese-speaking Mongols is most likely going to survive due to the presence of urban ethnic communities. The multilingual situation in Inner Mongolia does not appear to obstruct efforts by ethnic Mongols to preserve their language. Although an unknown number of Mongols in China, such as the Tumets, may have completely or partially lost the ability to speak their language, they are still registered as ethnic Mongols and continue to identify themselves as ethnic Mongols. The children of inter-ethnic Mongol-Chinese marriages also claim to be and are registered as ethnic Mongols.
Mongolian belongs to the Mongolic languages. The delimitation of the Mongolian language within Mongolic is a much disputed theoretical problem, one whose resolution is impeded by the fact that existing data for the major varieties is not easily arrangeable according to a common set of linguistic criteria. Such data might account for the historical development of the Mongolian dialect continuum, as well as for its sociolinguistic qualities. Though phonological and lexical studies are comparatively well developed, the basis has yet to be laid for a comparative morphosyntactic study, for example between such highly diverse varieties as Khalkha and Khorchin.