The ethnic group was first known to Westerners in the 1920s, when the language was already considered in severe decline (Kerr 1927). In the 1970s, David Bradley began working on the language in the several areas where it was still used, by which time it was already extinct in two of the locations given by Kerr (1927) about 50 years earlier. The people were then forced from two of these villages when the
Electricity Generating Authority of Thailand built dams over the
Kwae Yai and
Khwae Noi River (Bradley 1989). Because of the displacement of the people of an already declining language, the language is considered especially vulnerable to extinction. The last children speakers were in the 1970s and the children now speak
Thai as their first language. ==Classification==