宣光省
Sui is also spoken in Hồng Quang Village, Chiêm Hoá District, Tuyên Quang Province (62 km northwest of Chiêm Hoa City). In Vietnam, the Sui are known as Thủy, but are officially classified with the Pà Thẻn people. The Sui numbered only 55 people as of the 1982 Vietnamese census, and numbered about 100 people as of 2001. Since Pa-Hng (Pà Thẻn) and Tày are also spoken in Hồng Quang Village, many Sui are also fluent in those two languages.