Excluding immigrants the languages spoken by the people of Bengal belong to one or other of four linguistic families - Aryan, Dravidian, Munda and Tibeto-Burman.
The Aryan languages are spoken in the plains by almost the whole population; the Munda and Dravidian in the Chota Nagpur plateau and adjoining tracts; and the Tibeto-Burman in Darjeeling, Sikkim and Jalpaiguri.
Although the northern limits of the Tsanpo basin are not :sufficiently well known to locate the Indo-Tibetan watershed even approximately, there exists some scattered evidence of the nature of that strip of Northern Hima p laya on the Tibeto-Nepalese border which lies between the line of greatest elevation and the trough of the snowy Tsanpo.
Tibeto-Chinese Family Tibeto-Burman Sub-family (9,560,454) Siamese-Chinese Sub-family (1,724,085) Dravidian Family (5 6, 5 1 4,5 2 4)
Of the Tibeto-Chinese family, the Tibeto-Burman sub- :family, as its name implies, is spoken from Tibet to Burma; while the Siamese-Chinese subfamily is represented by the Karens .and Shans of Burma.