At the beginning of the first millennium. a people known as the lai migrated from whal is now southern Chinas into the Chao Phraya River valley. When the Tai first arrived. the region was inhabited by Austro-Asiatic groups speaking Mon and Khmer; the present-day Thais are the product of the assimilation and fusion of these three groups. Many Thais still live in southern China (particularly in Yunnan, Guangdong, and Guangxi). Today four subdivisions of Thais are recognized in the country; the central Thais (from the region between Sukhothai and Phetchaburi), who speak the standard Thai taught in schools; the Pak Isan Thais (a mixture of Thai and Khmer in the northeast), who also speak standard Thai; the Pak Tai Thais (south of Phetchaburi), who have a darker complexion and speak a dialect largely incomprehensible to central Thats; the northern Thais, who speak a different dialect and who are a fusion of Thai immigrants with Karens and Lawas (Austro-Asiatic). Each of these groups had largely independent histories until rccent centuries.
The Thais