A branch of the Tai languages WordNet 3.0

A branch of the Tai languages, spoken in central and northeast Vietnam, near China border, Cao Bang, Lang Son, Bac Giang, Bac Kan, Thai Nguyen, Ha Giang, Tuyen Quang, Yen Bai, and Hai Duong provinces, Bac Thai, Quang Ninh, Ha Bac, south in Lam Dong Province,Tung Nghia and Song Mao and possibly in Laos Open English WordNet

Tày or Thổ is the major Tai language of Vietnam, spoken by more than a million Tày people in Northeastern Vietnam. Wikipedia

Tai language of Vietnam Wikidata