|Nuba Mountains, Sudan|
The Kadu languages, also known as Kadugli–Krongo or Tumtum, are a small language family of the Kordofanian geographic grouping, once included in Niger–Congo but since Thilo Schadeberg (1981) widely seen as Nilo-Saharan. However, there is little evidence for either classification, and a conservative classification would treat the Kadu languages as an independent family.
There are three branches:
- Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2017). "Kadugli–Krongo". Glottolog 3.0. Jena, Germany: Max Planck Institute for the Science of Human History.
- Gerrit Dimmendaal, 2008. "Language Ecology and Linguistic Diversity on the African Continent", Language and Linguistics Compass 2/5:843ff.
- Thilo C. Schadeberg. 1981. "The classification of the Kadugli language group". Nilo-Saharan, ed. by T. C. Schadeberg and M. Lionel Bender, pp. 291–305. Dordrecht: Foris Publications.