Nilo-Saharan
I
The Nilo-Saharan
languages are found across this region today, although fragmented by the
subsequent expansion of Berber.
Their greatest area of
diversity is in the Ethio-Sudan borderlands where they may have existed as
foragers for a long period.
The internal structure of the phylum is
disputed (Bender vs. Ehret), though not its internal diversity nor the
location of that diversity
The genealogical tree
follows Bender which very much corresponds to my own research