The Tai speaking tribes are the more predominant in East [ Northeastern ] Thailand [ Isan ]. The 7 Tai Groups include, the Lao, the Tai Lao Isan [ or I san Tai ], the Khorat Tai, the Tai Yor, the Lao Wiang, the Lao Lom [ Tai Loei or Tai Dan ] and the Phu Tai. The significant groups in numbers are the Lao Isan [ in excess of 20 million ] and the Korat Tai [ 400,000 ]. The other groups each number between 20,000 to 80,000.
The Mon Khmer language group of the Austro Asiatic language group in I san comprise the Mon [ Nakhon Ratchasima ], the So and Kaleung [ Mukdahan, Sakhon Nakhon and Nakhon Phanom ], the Thavung [ Sakhon Nakhon ], Seak [ Nakhon Phanom ], Bru [ Ubon Ratchathani ], Chaobon [ Chaiyaphun and Nakhon Ratchasima ] and the Kui [ Surin, Si Sa Ket and Ubon Ratchathani ].
There are altogether 19 Mon Khmer speaking groups in Thailand with 8 of these in Isan. Another major group are the Khmer who are the same as the Cambodians in Cambodia and who were historically significant in Thailand history and particularly the region of North East Thailand.