Western Siouan languages
The Western Siouan languages, also called Siouan proper or simply Siouan, are a large language family native to North America. They are closely related to the Catawban languages, sometimes called Eastern Siouan, and together with them constitute the Siouan (Siouan–Catawban) language family.
Duan language
Duan, Doan, or Halang Doan, is a language spoken by more than four thousand people on either side of the Laotian–Vietnamese border. There are some 2,346 speakers in Attopu Province, Laos, and another couple of thousand in Kon Tum Province, Vietnam. It is too poorly known to classify completely and may be mutually intelligible with Takua, Kayong, Halang, and Rengao. Might be a part of the Xơ Ɖăng ethnic group.