Peopling of Thailand

That population is usually described in terms of several movements of people. Tai speakers moved south from what is now southern China into the river valleys of the north and later into the central plain, where an Austroasiatic-speaking population was already established; their descendants now form the large majority. Chinese immigration, drawn chiefly from the southern provinces, runs from at least the 13th century and became heavy in the 19th and early 20th. Three smaller streams reached the northern hills later, Loloish groups by way of Tibet, Sichuan and Yunnan, Hmong–Mien groups from southern China through Laos in the second half of the 19th century, and Karen groups from Burma, whose movement continued as refugee flight through the 20th century.

Chris Baker and Pasuk Phongpaichit caution against treating such movements as neat layers. Gene pools and forms of knowledge need not travel together, and as the archaeological record has thickened the continuities have become more striking than the breaks.

Tai migration from southern China

The Tai migration from the northern mountains into Thailand and Laos was a slow process, with the Tai generally remaining near the mountainous area in the region, where they were able to use their specialized agricultural knowledge relating to the use of mountain water for rice production. Baker and Pasuk state the point more precisely. Rice was long established in these hills; what the Tai may have brought was a set of techniques for a higher and more secure yield, developed in the karst country of southwest China, using dikes, retention dams, bamboo pipes, stone-lined ditches and lifting devices. Their settlement sites share a topography of a large basin, often at a confluence, with hill streams that can be tapped for irrigation. The earliest Tai settlements in Thailand were in the river valleys in the northern reaches of the country.

Eventually, the Tai settled the central plains of Thailand (which were covered with dense rainforest) and displaced and inter-bred with the pre-existing Austroasiatic population. The genetic evidence for that earlier population is direct. DNA from skeletons of the upper Mun basin dated between 1500 and 500 BCE has its closest living match in the Chao Bon or Nyah Kur, a Mon-Khmer group still living in the nearby hills. The languages and culture of the Tai eventually came to dominate the regions of both modern-day Laos and Thailand. In more recent times, many of the Tai tribes of Laos also migrated west across the border, establishing communities in Thailand. The Laotian Tai ethnic groups, often referred to as the Lao, are largely clustered in the Isan region of Thailand.

Origin of the Tai peoples

Comparative linguistic research seems to indicate that the Tai peoples were a Proto-Tai–Kadai speaking culture of southern China and dispersed into mainland Southeast Asia. Many linguists propose that the Tai–Kadai peoples may be genetically connected with Proto-Austronesian speaking peoples. Laurent Sagart (2004) hypothesized that the Tai–Kadai peoples migrated from a homeland on the island of Taiwan, where they spoke a dialect of Proto-Austronesian or one of its descendant languages. The ancestors of the modern Tai-Kadai peoples sailed west to mainland China and possibly traveled along the Pearl River, where their language greatly changed from other Austronesian languages under the influence of Sino-Tibetan and Hmong–Mien language infusion. Aside from linguistic evidence, the connection between Austronesian and Tai-Kadai can also be found in some common cultural practices. Roger Blench (2008) demonstrates that dental evulsion, face tattooing, teeth blackening and snake cults are shared between the Taiwanese Austronesians and the Tai-Kadai peoples of Southern China. Baker and Pasuk caution against reading such reconstructions as layers. Peter Bellwood and Robert Blust proposed that Mon-Khmer spread with rice agriculture and that later waves superseded the hunter-gatherers, but gene pools and forms of knowledge need not travel together, and as the archaeological record has thickened the continuities have become more striking than the discontinuities.

James R. Chamberlain (2016) proposes that the Tai-Kadai (Kra-Dai) language family was formed as early as the 12th century BCE in the middle of the Yangtze basin, coinciding roughly with the establishment of the Chu state and the beginning of the Zhou dynasty. Following the southward migrations of Kra and Hlai (Rei/Li) peoples around the 8th century BCE, the Yue (Be-Tai people) started to break away and move to the east coast in the present-day Zhejiang province, in the 6th century BCE, forming the state of Yue and conquering the state of Wu shortly thereafter. According to Chamberlain, Yue people (Be-Tai) began to migrate southwards along the east coast of China to what are now Guangxi, Guizhou and northern Vietnam, after Yue was conquered by Chu around 333 BCE. There the Yue (Be-Tai) formed the Luo Yue, which moved into Lingnan and Annam and then westward into northeastern Laos and Sip Song Chau Tai, and later became the Central-Southwestern Tai, followed by the Xi Ou, which became the Northern Tai).

The Tai peoples, from Guangxi began moving south – and westwards in the first millennium CE, eventually spreading across the whole of mainland Southeast Asia. Based on layers of Chinese loanwords in proto-Southwestern Tai and other historical evidence, Pittayawat Pittayaporn (2014) proposes that the southwestward migration of southwestern Tai-speaking tribes from the modern Guangxi to the mainland of Southeast Asia must have taken place sometime between the 8th–10th centuries. Tai speaking tribes migrated southwestward along the rivers and over the lower passes into Southeast Asia, perhaps prompted by the Chinese expansion and suppression.

Tai ethnic fusion

Over the centuries, the Tai intermarried and absorbed many of the other populations who shared the region or held political power in it, particularly populations of Mon–Khmer, Burmese, and Chinese descent. This fusion of ethnicity has led to considerable genetic diversity in the modern Thai people, and has resulted in a Tai population that differs in culture, language, and apparel from the Tai ethnic groups who remained in China. Many of the individual Tai ethnic groups have assumed a common Thai identity and have adopted Thai cultural norms.

Individual Tai ethnic groups in Thailand

There are more than 30 distinct Tai ethnic groups in Thailand, contributing nearly 85 percent of the nation's population. The genetic stratification of the ethnic clades of the Tai ethnicity is an ongoing topic of debate among linguists and other social scientists.