Ethnic groups in Thailand

[1] From approximately the 7th until the 13th centuries, the Tai, who may have originated in what is now Guangxi in China and bordering areas of Northwest Vietnam, gradually populated the Mekong, Chao Praya, and Salween river valleys, fuelled by a sophisticated rice production system.

From the 16th to the 18th centuries the Burmese expanded east, occupying Lan Na and parts of the Xishuangbanna and eventually destroying Ayutthaya.

[1] Under the Bangkok-based Chakri dynasty, Siam formally incorporated and integrated large numbers of ethnically Laotian people, themselves formed of various subgroups.

Siam brought the remaining Lan Xang city-states of Vientiane (destroyed in 1827) and Champasak under direct control in the 19th century.

What remained of Lan Na became a vassal until 1896, when it was formally annexed, incorporating large numbers of Kham muang speakers, together with the various ethnic groups sometimes called 'hill tribes', such as the Karen.

When Kedah was ceded to the English under the Anglo–Siamese Treaty of 1909, in exchange for what became Satun Province, Thailand thereby cemented its official rule over hundreds of thousands of Malay people.

In the early Chakri dynasty period, Siamese armies had invaded areas of Laos and returned with large numbers of prisoners of war, especially Phuan and Tai Dam peoples, who were subsequently resettled in the central plains.

During the nation-building era, Siam's ethnic map became more varied, as the majority of the peoples of the Khorat plateau, once part of Lan Xang empire, were formally integrated into Siam, incorporating more Lao, Khorat, and Phu Thai, but also smaller ethnic groups such as the Yoy and So, together with the Khmu, Kuy, and Nyahkur along the Khmer border.

For the most part the Dai/Tai/Thai occupied the more fertile intermontane basins and valleys, while the less powerful groups lived at the less rich higher elevations.

[14] Vestiges of this dichotomy remain today: for example, 30 percent of ethnic minority children in Thailand cannot read by second grade.