A family of about 150 languages which includes Vietnamese, Munda (eastern India), Mon (southwest Burma), Khmer (Kampuchea), and several minor language groups including Nicobarese, and Aslian of peninsular Malaysia. Vietnamese, Khmer, and Mon are culturally the most important of these and have the longest recorded history. Khmer is spoken primarily in Cambodia, Mon in Thailand and Myanmar (Burma). Vietnamese and Khmer, with the largest number of speakers, are the national languages, respectively, of Vietnam and Cambodia. Austro-Asiatic was once the main linguistic family of mainland Southeast Asia and eastern India, but its speakers have become geographically split into the Tibeto-Burman, Thai, and Austronesian languages.