Identification. The Hmong have migrated to Southeast Asia from the mountainous parts of southwestern China, where many still remain. They have settled in the mountainous regions of northern Laos, northern Vietnam, and northern Thailand, and there are small groups of Hmong in Myanmar (Burma) near the Chinese border. Since the ending of the Indochina wars large numbers of Hmong refugees from Laos have been resettled in Western countries, including the United States. There are two main cultural divisions of the Hmong in Southeast Asia, marked by differences of dialect and custom, between the White Hmong and the Green Hmong (who pronounce their name as "Mong"). Hmong religion is based on domestic ancestral worship and shamanism, and they speak dialects of the Miao Branch of the Miao-Yao Language Family.
Location. Southwestern China, Myanmar, and northern Indochina form a unified geographical zone characterized by four main mountain ranges outcropping from the eastern Himalayas and the Tibetan plain, with a semitropical climate and dense tropical rain forest in some areas. At around 1,000 meters deciduous trees give way to evergreen forest. Mountain peaks range from 2,535 meters in Thailand to 7,470 meters in southern China. North-south-running mountain ranges separate fertile alluvial river valleys united in the past only by a network of caravan routes.
Demography. There are some 2 million Hmong speakers in China, approximately 200,000 in Laos, 300,000 in Vietnam, and 50,000 in Thailand. More than 30,000 others are in refugee camps along the Thai border with Laos. More than 100,000 have been resettled in Western countries.
Linguistic Affiliation. Hmong forms part of the Western Branch of the Miao languages, which also include Hmu and Kho Xyong. Miao is related at its upper levels to the Yao dialects, from which a Proto-Miao-Yao can be reconstructed. No relationship to other languages has been firmly established, although the whole group has been influenced strongly by Chinese. The Miao-Yao languages are usually classed as Sino-Tibetan, although some scholars disagree with this. Hmong has eight tones and a complex phonology.