Nilo-Saharan specialists have vacillated on a genealogical relationship between the Koman and Gumuz languages of Ethiopia and (South) Sudan, a relationship called Komuz. Greenberg (1963) had included Gumuz in the Koman language family. Bender (1989, 1991) classified them together in a distant relationship he called Komuz, but by 1996 he had reversed himself, though he kept both groups in core Nilo-Saharan.