Mon-Khmer languages (mōn-kəmâr`), group of languages frequently considered as a subfamily of the Southeast Asian family of languages. See Southeast Asian languages Southeast Asian languages, family of languages, sometimes also called Austroasiatic, spoken in SE Asia by about 80 million people. According to one school of thought, it has three subfamilies: the Mon-Khmer languages, the Munda languages, and the Annamese-Muong
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Mon-Khmer languages

Family of about 130 Austroasiatic languages, spoken by more than 80 million people in South and Southeast Asia. Vietnamese has far more speakers than all other Austroasiatic languages combined. Other languages with many speakers are Muong, with about a million speakers in northern Vietnam; Khmer; Kuay (Kuy), with perhaps 800,000 speakers; and Mon, spoken by more than 800,000 people in southern Myanmar and parts of Thailand. Of all the Mon-Khmer languages, only Mon, Khmer, and Vietnamese have written traditions dating earlier than the 19th century. Old Mon, which is attested from the 7th century, was written in a script of South Asian origin that was later adapted by the Burmese (see Mon kingdom; Indic writing systems). Typical phonetic features of Mon-Khmer languages are a large vowel inventory and lack of tone distinctions.