Duan, 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 Daksut, and Rengao.
- ^ Duan at Ethnologue (17th ed., 2013)
- ^ Nordhoff, Sebastian; Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2013). "Halang Doan". Glottolog 2.2. Leipzig: Max Planck Institute for Evolutionary Anthropology.