The family was proposed by Joseph Greenberg in The Languages of Africa under the name Adamawa–Eastern as a primary branch of the Niger–Congo family, which is in turn divided in two branches, Adamawa (e.g. Niellim) and Ubangian (e.g. Azande (Zande language), Ngbandi, on which the creole Sango is based).
[2] Roger Blench replaced Adamawa–Ubangi with a Savannas family, which includes Gur, Ubangian and the various branches of Adamawa as primary nodes.
Dimmendaal (2008) doubts that Ubangian is a subfamily of Niger–Congo at all, preferring to classify it as an independent family until proven otherwise.
The noun class system is no longer fully productive in all languages.
In Williamson and Blench (2000), since abandoned, the internal classification was:[5] Leko Duru Mumuye/Yendang Nimbari Mbum Bua Kim Day Waja Longuda Jen Bikwin Yungur Ba (=Kwa) Kam Fali Gbaya Banda Ngbandi Sere Ngabaka Mba Zande