Thai is the national and official language of Thailand and the native language of the Thai people, Thailand's dominant ethnic group. Thai is a member of the Tai group of the Tai–Kadai language family.

Thailand is home to other related Tai languages, including:
  • Isan
  • Khorat Thai
  • Northern Thai
  • Southern Thai
  • Phu Thai
  • Phuan
  • Shan
  • Nyaw language
  • Song

Most speakers of dialects and minority languages speak Central Thai as well, since it is the language used in schools and universities all across the kingdom.