Family of closely related languages spoken in Southeast Asia and southern China by more than 80 million people.
According to a widely used classification, Tai comprises three branches. The Southwestern group includes Thai, the national language of Thailand; northeastern Thai and Lao, spoken in eastern Thailand and Laos; Pak Tay (South Thai), spoken in southern Thailand; Shan, spoken in eastern and northern Myanmar; and Tai Dam (Black Tai) and Tai Don (Tai Khaw, or White Tai), spoken mainly in North Vietnam. The Central group includes Nung and South Zhuang, a dialect chain in northern Vietnam and China's Guangxi province; and Tay (Thô), spoken in the same area. The Northern group includes Buyi and North Zhuang, a dialect chain spoken in Guangxi, Guizhou, and Yunnan, China. All Tai languages are tone languages. Most scholars believe the Tai family is related to a number of other languages spoken by minority peoples of southern China and northern Vietnam. Together with Tai, the entire group has been named the Kadai or Tai-Kadai family.