ABSTRACT
Thai (Siamese, Central Thai) belongs to the Tai language family, a subgroup of the Tai-Kadai, Kra-Dai or Kam-Tai family. A number of linguists now regard Kam-Tai, along with Austronesian, as a branch of Austro-Tai, although this hypothesis remains controversial. All members of the Tai family derive from a single proto-parent designated as Proto-Tai. Linguistic research has shown the area near the border of northern Vietnam and southeastern China as the probable place of origin for the Tai languages. Today the Tai family includes languages spoken in Assam, northern Myanmar, all of Thailand including the peninsula, Laos, northern Vietnam and the Chinese provinces of Yunnan, Guizhou and Guangxi. Linguists, notably Fang Kuei Li, divide these languages into a Northern, a Central and a Southwestern branch. Others, in particular William J. Gedney and A.-G. Haudricourt, view the Central and Southwestern branch as a single group, suggesting that a clear boundary of isoglosses between the two branches is difficult to distinguish. In the tripartite division, Thai falls into the Southwestern branch.
