Previously, the four Niger–Congo language groups along with the Nilo-Saharan Kadu group were classified together as the Kordofanian languages. However, Kordofanian is no longer considered a valid family.[3]
Almost all of the languages spoken in the Nuba Mountains are indigenous to the mountains and found nowhere else. The only exceptions are the Daju languages, the rest of which belong to Western Daju and are found in eastern Chad, and Sudanese Arabic, which is spoken in the rest of Sudan.
Internal classifications
The languages of the Nuba Mountains belong to several distinct subdivisions of their respective languages families.
Note: Atlantic–Congo is a major division of Niger–Congo which only excludes the Mande, Ijoid and Dogon languages of West Africa, along with the Katla and Rashad languages of the Nuba Mountains.
Eastern Sudanic is a large division of Nilo-Saharan spoken throughout the upper Nile region. Kir–Abbaian and Astaboran are the two branches of Eastern Sudanic, roughly distributed in the north and south of the region, respectively.
The Nubian languages are spoken mostly in northern Sudan and southern Egypt. Only Midob and the extinct Birgid are found in southern Sudan, along with the Hill Nubian languages of the Nuba Mountains.
MacDiarmid, P.A. and D.N. MacDiarmid. 1931. The languages of the Nuba Mountains. Sudan Notes and Records 14:149-162.
Stevenson, Roland C. 1956–57. A survey of the phonetics and grammatical structures of the Nuba Mountain languages, with particular reference to Otoro, Katcha and Nyimang. Afrika und Übersee 40:73-84, 93–115; 41:27-65, 117–153, 171–196.