Phu Thai language

Phu Thai (Phuu Thai; Thai, Phu Thai: Phasa Phuthai, ภาษาผู้ไท or ภูไท) is a Southwestern Tai language spoken in Laos, Thailand and Vietnam. Although it appears different from the Isan and the Lao languages, it is spoken in areas where these languages are predominant and has been influenced by them. Comparisons of Phu Thai with other Tai languages such as Tay Khang^{[citation needed]} have not yet been done systematically enough to yield convincing results.
Another aspect of Phu Thai is its contact with the Katuic languages, a branch of the Austroasiatic languages. Whether in the Phu Thai areas of Central Laos or in more recent locations of Northeastern Thailand, one can find, along with Phu Thai, a few Katuic dialects known locally as Bru, So or Katang. James R. Chamberlain (2012) focusing on anthropological issues describes “the Phou Thay – Brou relationship” as a “symbiosis” and states that “the Phou Thay – Brou relationship has never evolved into a feudal system”.