In 1963, Joseph Greenberg added them to the Niger–Congo family, creating his Niger–Kordofanian proposal. The Kordofanian languages have not been shown to be more distantly related than other branches of Niger–Congo, however, and they have not been shown to constitute a valid group. Today, the Kadu languages are excluded, and the others are usually included in Niger–Congo proper.[citation needed]
Roger Blench notes that the Talodi and Heiban families have the noun class systems characteristic of the Atlantic–Congo core of Niger–Congo but that the two Katla languages have no trace of ever having had such a system. However, the Kadu languages and some of the Rashad languages appear to have acquired noun classes as part of a Sprachbund rather than having inherited them. Blench concludes that Talodi and Heiban are core Niger–Congo whereas Katla and Rashad form a peripheral branch along the lines of Mande.[citation needed]
Heiban, Katloid, and Talodi are also grouped together in an automated computational analysis (ASJP 4) by Müller et al. (2013).[2] However, since the analysis was automatically generated, the grouping could be either due to mutual lexical borrowing or genetic inheritance.
The number of Rashad languages, also called Tegali–Tagoi, varies among descriptions, from two (Williamson & Blench 2000), three (Ethnologue), to eight (Blench ms). Tagoi has a noun-class system like the Atlantic–Congo languages, which is apparently borrowed, but Tegali does not.
Quint (2020) suggests that Proto-Kordofanian can be reconstructed from the Heibanian, Talodian, Rashadian, Katloid, and Lafofa languages. His Proto-Kordofanian reconstructions are as follows:[4]
^Müller, André, Viveka Velupillai, Søren Wichmann, Cecil H. Brown, Eric W. Holman, Sebastian Sauppe, Pamela Brown, Harald Hammarström, Oleg Belyaev, Johann-Mattis List, Dik Bakker, Dmitri Egorov, Matthias Urban, Robert Mailhammer, Matthew S. Dryer, Evgenia Korovina, David Beck, Helen Geyer, Pattie Epps, Anthony Grant, and Pilar Valenzuela. 2013. ASJP World Language Trees of Lexical Similarity: Version 4 (October 2013).
^Gerrit Dimmendaal, 2008. "Language Ecology and Linguistic Diversity on the African Continent", Language and Linguistics Compass 2/5:842.
^Quint, Nicolas (2020). In: Vossen, Rainer and Gerrit J. Dimmendaal (eds.). The Oxford Handbook of African Languages, 239-268. Oxford: Oxford University Press.
^Schadeberg, Thilo C. 1981. A Survey of Kordofanian Vol 2: The Talodi Group. (Sprache und Geschichte in Afrika: Beiheft, 2.) Hamburg: Helmut Buske. 175pp.
^Schadeberg, Thilo C. 1981. A Survey of Kordofanian. Volume 1: The Heiban Group. Hamburg: Helmut Buske.
^Norton, Russell, and Thomas Kuku Alaki. 2015. The Talodi Languages: A Comparative-Historical Analysis. Occasional papers in the study of Sudanese languages 11:31-161.
P. A. and D. N. MacDiarmid. 1931. "The languages of the Nuba Mountains." Sudan Notes and Records 14: 149-162.
Carl Meinhof. 1915-1919. "Sprachstudien im egyptischen Sudan". Zeitschrift für Kolonialsprachen 9-9. "1. Tagoy." 6: 164-161. "2. Tumale". 6:182-205. "11. Tegele." 7:110-131. "12. Rashad." 7:132.
Thilo C. Schadeberg. 1981a. A survey of Kordofanian. SUGIA Beiheft 1-2. Hamburg:Helmut Buske Verlag.
Thilo C. Schadeberg. 1981b. "Das Kordofanische". Die Sprachen Afrikas. Band 1: Niger–Kordofanisch, ed. by Bernd Heine, T. C. Schadeberg, Ekkehard Wolff, pp. 117–28 SUGIA Beiheft 1-2. Hamburg:Helmut Buske Verlag.
Brenda Z. Seligmann. 1910-11. "Note on the language of the Nubas of Southern Kordofan." Zeitschrift für Kolonialsprachen 1:167-188.
Roland C. Stevenson. 1956-57. "A survey of the phonetics and grammatical structure of the Nuba Mountains languages, with particular reference to Otoro, Katcha, and Nyimang." Afrika und Übersee 40:73-84, 93-115; 41:27-65, 117-152, 171-196.
Tucker, A. N. and M. A. Bryan. 1956. The Non-Bantu Languages of North-Eastern Africa. (Handbook of African Languages, Part III.) Oxford University Press: London.
A. N. Tucker and M. A. Bryan. 1966. Linguistic Analyses/The Non-Bantu Languages of North-Eastern Africa. (Handbook of African Languages.) Oxford University Press: London.
Tutschek, Lorenz. 1848. "Über die Tumale-Sprache." Gelehrte Anzeigen, herausgegeben von Mitgliedern der k. bayer.Akademie der Wissenschaften. Nrs. 91-93; Spalten 729-52. (=Bulletin der königl. Akademie der Wissenschaften. Nrs. 29-31.)
Tutschek, Lorenz.. 1848-50. "On the Tumali language". Proceedings of the Philological Society for 1846-47 and 1847-48. Vol 3:239-54. Proceedings of the Philological Society for 1848-49 and 1849-50. Vol. 4:138-9.