The Thai (or Tai) are the main ethnic group of Thailand and are part of the larger Tai ethnolinguistic peoples found in Thailand and adjacent countries in Southeast Asia as well as southern China. Their language is the Thai language, which is classified as part of the Kradai family of languages, and the majority of Thai are followers of Theravada Buddhism. The term Thai people may also refer to the population of Thailand in general, and not only to ethnic Thais. In this sense, they are also known as Thailanders.
The Thais can be broken down into various regional groups including the main Thai, northeastern, northern, and southern Thai with their own regional dialects of their mutually intelligible Thai language. Modern Central Thai has become more dominant due to official government policy, which was designed to assimilate and unify the disparate Thai in spite of ethnolinguistic and cultural ties between the northeastern Thai people and the people from Laos for example.
The modern Thai are predominantly Theravada Buddhist and strongly identify their ethnic identity with their religious beliefs that include aspects of ancestor worship (see Culture of Thailand). Indigenous arts include Muay Thai (the Thai version of South East Asian kick boxing), Thai dance, Makruk (Thai Chess), and Nang yai (shadow play).
The Thai have a literacy rate hovering at 94%  (one of the highest in Southeast Asia) and a strong predilection towards education and national development.
 (Source: Wikipedia)