Concept
Tai peoples are the populations who speak (or formerly spoke) the Tai languages. There are a total of about 93 million people of Tai ancestry worldwide, with the largest ethnic groups being Dai, Thais, Isan, Tai Yai (Shan), Lao, Tai Ahom, and Northern Thai peoples. The Tai are scattered through much of South China and Mainland Southeast Asia, with some (e.g. Tai Ahom, Tai Khamti, Tai Phake, Tai Aiton) inhabiting parts of Northeast India. Tai peoples are both culturally and genetically very similar and therefore primarily identified through their language. Speakers of the many languages in the Tai branch of the Tai–Kadai language family are spread over many countries in Southern China, Indochina and Northeast India. Unsurprisingly, there are many terms used to describe the distinct Tai peoples of these regions. According to Michel Ferlus, the ethnonyms Tai/Thai (or Tay/Thay) would have evolved from the etymon *k(ə)ri: 'human being' through the following chain: kəri: > kəli: > kədi:/kədaj (-l- > -d- shift in tense sesquisyllables and probable diphthongization of -i: > -aj). This in turn changed to di:/daj (presyllabic truncation and probable diphthongization -i: > -aj). And then to *dajA (Proto-Southwestern Tai) > thajA2 (in Siamese and Lao) or > tajA2 (in the other Southwestern and Central Tai languages by Li Fangkuei). Michel Ferlus' work is based on some simple rules of phonetic change observable in the Sinosphere and studied for the most part by William H. Baxter (1992). The ethnonym and autonym of the Lao people (lǎo 獠) together with the ethnonym Gelao (Gēlǎo 仡佬), a Kra population scattered from Guìzhōu (China) to North Vietnam, and Sino-Vietnamese 'Jiao' as in Jiaozhi (jiāo zhǐ 交趾), the name of North Vietnam given by the ancient Chinese, would have emerged from the Austro-Asiatic *k(ə)ra:w 'human being'. The etymon *k(ə)ra:w would have also yielded the ethnonym Keo/ Kæw kɛːwA1, a name given to the Vietnamese by Tai speaking peoples, currently slightly derogatory.