Identification. The Kmhmu are the indigenous inhabitants of northern Laos prior to the southwestward migrations of Tai-speaking peoples. They have expanded within the last two centuries to bordering areas of Thailand, China, and Vietnam, and since 1975 to the United States, France, and Canada. In the Kmhmu language, "Kmhmu'" means "person, human"; they were formerly known by the pejorative term "Kha" or "Xa" (from Tai languages), meaning "slave, serf." Kmhmu are divided into a number of local groups known as tmooy (guest or stranger) ; the word refers to people who are like us but unknown to us, and may even include members of other neighboring Mon-Khmer ethnic groups. Another term, jé', refers to people who are not like us (for instance, Lao, Tai, and Hmong). The tmooy groups are believed by some scholars to be the remnants of ancient political divisions, although it is more likely they are simply differentiated by geography. The Tmooy Ou are those living near the Ou river; the Tmooy Yuan are those who formerly paid tribute to the Tai Yuan overlord; the Tmooy Cvaa are those living in the Luang Prabang region, formerly Muang Cvaa. People also may be distinguished by which negative particle they use: Tmooy Al are speakers of a northern dialect and Tmooy Am speakers of a southern one.
Location. Kmhmu traditionally lived at the lower elevations of mountain ridges in northern Indochina. They once centered on the valleys of the Nam Ou, Nam Tha, and Nam Beng rivers and their confluence with the Mekong river. Following Tai migrations into this area, Kmhmu were dispersed in every direction, often absorbing smaller related ethnic groups. They inhabit tropical forests watered by monsoons, with a rainy season that extends from May or June to September or October.
Demography. The largest number of Kmhmu live in the Lao People's Democratic Republic, numbering 400,000 in the 1985 census; they comprise 10 percent of the country's population and constitute the largest single minority ethnic group. Kmhmu in Thailand number from 5,000 to 50,000; in China there are approximately 2,000; and in Vietnam there were 32,000 in 1979. In mountainous regions the population density is very low; there are also small urban populations in cities such as Luang Prabang, Vientiane, Lampang, and even Bangkok. Some 3,000 Kmhmu now live in North America, and approximately 750 live in France.
Linguistic Affiliation. Kmhmu speak a number of mutually intelligible dialects of the Kmhmu language, which is the largest member of the Khmuic Group of the Northern Mon-Khmer Branch of the Austroasiatic Language Family. Their territory is surrounded by groups speaking smaller languages of the Khmuic Family; in many cases these people also speak Kmhmu itself. Kmhmu are almost all at least bilingual, speaking their mother tongue and whatever is the locally dominant Tai language (Lao, Northern Thai, Tai Dam, Lue). The contemporary vocabulary includes a large proportion of Tai loanwords, many borrowed centuries ago and others borrowed more recently. Kmhmu in Vietnam, the United States, and France also speak the languages of those countries as a third language. Their own language includes two main dialect groups: Southern Kmhmu dialects maintain a historical distinction between voiced and voiceless initials, whereas Northern Kmhmu dialects have replaced this with a distinction between low tone and high tone.