The Encyclopedia of Language and Linguistics1 classified the Khasi Language to belong to the sub-family of Northern Mon-Khmer, a subset of the Austroasiatic family of languages, identified ever since the second half of the nineteenth century.
It is historically believed that the Austroasiatic family of languages is thought to be the first to be spoken in ancient India throughout the Indian subcontinent by hunter/gatherers who were later assimilated - initially by the agriculturalist Dravidian settlers and later by the Indo-Aryan peoples arriving from northwestern India. Anthropological and Genetics studies conducted from time to time also indicated that the Austro Asiatic tribes/group of tribal may be the earliest inhabitant of India.
J.H. Hutton is of the view that the Austro-Asiatic was at one time the most widely spread language in the world; from central India to New Zealand and from Madagascar up to Eastern Island (West of South America). As far as 169 Austro-Asiatic languages have been identified so far. According to Lewis (2009)2 Austroasiatic is the eighth largest language family in the world in terms of the number of native speakers (104 million).