Khorat Thai or Korat Thai (Thai: ไทยโคราช) people refers to an ethnic group named for their main settlement area in Nakhon Ratchasima Province, unofficially called "Korat". Korat Thai people call themselves Tai Berng (ไทยเบิ้ง), Tai Derng (ไทยเดิ้ง), or Tai Korat (ไทยโคราช). Other tribes in northern Thailand also refer to them by those names.
The proposed theories of the origin of the name Tai berng are:
- From its meaning, berng means some or few. Thai Khorat people lived in three major kingdoms: central Thai kingdoms (Ayutthaya, Thonburi, and Bangkok), Lao Kingdom, and Cambodia Kingdom. People who live in the Khorat area are of different origin, e.g., Thai, Lao, Khmer, Kui, and blended their cultures and beliefs together into their own culture.
- It may be from their commonly used word, berng is a word unique to the Thai Khorat people, and it is frequently used in their conversation.
Thai Khorat people have their own traditions and cultures called Khorat culture, which is similar to the culture of Thai people on the central plain, but their own unique words, dialect, costumes, songs, and beliefs are different from the rest of the Tai-speaking peoples. Some say Thai Khorat people speak a dialect which is halfway between Thai and Isan (Lao.)
Thai Khorat people occupy Nakhon Ratchasima and adjacent provinces:
- Nakhon Ratchasima Province: all districts, except for the northern part, e.g., Non Sung, Bua Yai.
- Saraburi Province: Wangmuang district
- Lopburi Province: Pattana Nikom, Chai Badal, Kok Samrong and Sra Bot districts
- Phetchabun Province: Srideph and Vichianburi districts
- Chaiyaphum Province: Chaturat and Bamnej Narong districts
- Buriram Province: Meung, Nang Rong, Laharn Sai, Nong Kee, and Lam Plai Mart districts
The Khorat Thai can be traced back at least to the late 18th century, when King Narai of the Ayutthaya Kingdom ordered a new city built as the eastern fortress of his kingdom. This was the origin of Nakhon Ratchasima city. The city thus marked the boundary between Ayutthaya and the Lao regions.