The Sán Dìu (also known as San Deo, Trai, Trai Dat and Man Quan Coc; ; Chữ nôm: ; Vietnamese alphabet: Người Sán Dìu) are a Yao ethnic group in northern Vietnam who speak Yue Chinese (Cantonese), a Sinitic language. They are believed to have migrated from Guangdong, China around 1600. The group's estimated population as of 2000 was 117,500; the 2019 census put the number at 183,004. They speak a variant of Cantonese, and it is suggested that some still speak Iu Mien. The major religions are Mahayana Buddhism and Taoism, with elements of animism and veneration of the dead. About 400 are adherents of the Catholic Church; a few are evangelical Protestants. This ethnic group is mainly concentrated around the Tam Đảo range in Thái Nguyên Province.