The Tây Sơn dynasty (Vietnamese: [təj ʂəːn], Vietnamese: Nhà Tây Sơn, Chữ Nôm: 茹西山, lit. 'House of Tây Sơn'; Vietnamese: triều Tây Sơn, officially Great Việt, was a dynasty of Vietnam. It was founded after three Nguyễn brothers from the village of Tây Sơn rebelled against the Lê dynasty, Nguyễn lords, and Trịnh lords. The Tây Sơn were led by these three brothers, referred to by modern Vietnamese historians as the Tây Sơn brothers because of their origin in the district of Tây Sơn. The Tây Sơn was later succeeded by the Nguyễn dynasty.

Vietnamese is an Austroasiatic language spoken primarily in Vietnam where it is the national and official language. Vietnamese is spoken natively by around 85 million people, several times as many as the rest of the Austroasiatic family combined. It is the native language of the Vietnamese (Kinh) people, as well as a second or first language for other ethnic groups in Vietnam.