Siouan languages
Authors who call the entire family "Siouan" distinguish the two branches as "Western Siouan" and "Eastern Siouan" or as "Siouan-proper" and "Catawban". Others restrict the name "Siouan" to the western branch and use the name "Siouan–Catawban" for the entire family. Generally, however, the name "Siouan" is used without distinction.
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.