Identification. The people officially known as the "Yao" in Thailand call themselves "Mian" or "Iu Mian." Historically, the Chinese called them "Yao," which means "dog" or "savage." In Yao, the word mian means "people." In Laos and Vietnam the word man also means "people."
Location. At present, Yao villages can be found in the provinces of Chiang Rai, Chiang Mai, Phayao, Lampang, Nan, Kamphaeng Phet, and Sukhothai in Thailand. Recently one village was also located in Tak Province. There has been a large-scale migration of the Yao from Chiang Rai Province to the south to find fertile land for farming; when the soil was exhausted they moved back and settled in Lampang. A number of the Yao who cultivated the land in the reserved forest were forced to settle in Kamphaeng Phet.
Demography. In 1986-1988 the Yao population in Thailand was officially placed at 36,140 persons, living in 4,814 households in 205 villages in 8 provinces: Chiang Mai, Chiang Rai, Phayao, Nan, Lampang, Kamphaeng Phet, Sukhothai, and Tak. The most populous provinces are Chiang Rai and Phayao. The Yao population is rapidly increasing owing to a high birth rate and immigration. In 1972 there were only 19,990 Yao people living in 111 villages.
Linguistic Affiliation. The Yao language is closely related to that of the Miao, both belonging to the Miao-Yao Pateng Branch of the Sino-Tibetan Language Family. Many Yao also speak Yunnanese or the closely related Mandarin Chinese; literacy in Chinese has long been found among them. In Thailand, the dialect spoken by the Yao of different regions is essentially the same, with the addition of some new words from Yunnanese and Thai. More men than women speak the Thai language, especially the northern Thai dialect.