Answer :
Bantu languages were the languages used in the whole sub Saharan Africa.
Explanation:
Bantu people of the sub Sahara territory were migrants and they migrated across the whole continent below Sahara.
They took their language with them and often became the ruling lass of the places they would reach and thus it was something that bound these empires together.
The empires that were formed used the Bantu tongue for a long time and they were also ethnically related thus.
The Bantu people were thus the ones that would migrate and rule the Sub Saharan region.