As a family of languages, Tai-Kadai may be considered to have many significant roots. Altogether, however, Tai-Kadai is considered to have originated several thousand years ago in the region of southern China, where it is thought that Proto-Tai-Kadai languages set the precedent for the eventual formation of this language family.
Migration and expansion in the region spread the forming language family, eventually forming two significant branches of the family. The Kadai branch includes languages such as Be-Tai and Kam-Sui, and the Tai branch includes languages such as Shan, Thai, and Zhuang. Interaction with other neighboring languages, like Chinese and Khmer, would eventually mold this language family into the modern iteration that can be heard today.