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.
Blench (2006) notes that Kadu languages share similarities with multiple African language phyla, including Niger-Congo and Nilo-Saharan, suggesting a complex history of linguistic convergence and contact.
There are three branches:
Hall & Hall (2004)
, based on Schadeberg (1987)  , classify the languages as follows.
Kanga, Kufa, Kursi, Lima, Shororo
Dafalla (2000) compares 179 cognates in Kadugli, Kamda, Kanga, Katcha, Keiga, Kufa, Miri, Shororo-Kursi, and Tulishi. Dafalla's (2000) results are similarly to those of Schadeberg (1989).
Blench, Roger. 2006.
The Kadu languages and their affiliation: between Nilo-Saharan, Niger-Congo and Afro-Asiatic. Insights into Nilo-Saharan Language, History and Culture. Al-Amin Abu-Manga, L. Gilley & A. Storch eds. 101-127. Köln: Rüdiger Köppe. Stevenson, Roland; Roger Blench (ed).
Comparative Kadu datasheets. Reh, Mechthild. 1983.
Die Krongo-Sprache (nììnò mó-dì): Beschreibung, Texte, Wörterverzeichnis. (Kölner Beiträge zur Afrikanistik, 12.) Berlin: Dietrich Reimer. Schadeberg, Thilo. 1994. Comparative Kadu wordlists. Afrikanistische Arbeitspapiere 40:11-48. University of Cologne.
Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2017). "Kadugli–Krongo". . Jena, Germany: Max Planck Institute for the Science of Human History. Glottolog 3.0
^ Gerrit Dimmendaal, 2008. "Language Ecology and Linguistic Diversity on the African Continent",
Language and Linguistics Compass 2/5:843 ff.
^ Blench, Roger. 2006.
The Kadu languages and their affiliation: between Nilo-Saharan, Niger-Congo and Afro-Asiatic. Insights into Nilo-Saharan Language, History and Culture. Al-Amin Abu-Manga, L. Gilley & A. Storch eds. 101-127. Köln: Rüdiger Köppe.
^ Hall, Marian and Hall, Edward. 2004. Kadugli-Krongo. Occasional Papers in the Study of Sudanese Languages 9. 57-68. Entebbe: Summer Institute of Linguistics Sudan.
^ Schadeberg, Thilo C. 1987. Kordofanian. In
The Niger-Congo languages, ed. by John Bendor-Samuel, pp. 66-80. Lanham: University Press of America.
Dafalla, Rihab Yahia. 2000.
A phonological comparison of the Katcha Kadugli language groups in the Nuba Mountains. M.A. Dissertation, University of Khartoum. Schadeberg, Thilo C. 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.