Tsat (also known as Utsat, Utset, Huihui, Hui, or Hainan Cham) is a language spoken on Hainan Island in China. Tsat is a member of the Malayo-Polynesian group within the Austronesian language family, and is related to the Cham languages, originally from the coast of present-day Vietnam.

Unusually for a Malayo-Polynesian language, Tsat has developed into a solidly tonal language, probably as a result of areal linguistic effects and contact with Chinese, Hlai /Li , and the other tonal languages of Hainan.