They speak mutually intelligible dialects and include groups such as the Banyoro, Banyankore, Banyarwanda and Bahaya.
They adopted pastoralism in the grasslands of Kagera with influence from the now extinct Tale southern Cushites and Sog Eastern Sudanic peoples who were their neighbors.
They adopted the word for cow (ente) between 100-500AD from the Sog Eastern Sudanic and the practice of cattle bleeding from the Tale southern Cushites.
[3][4] after 1200AD they split into two groups, with one group (the Proto-North Rutara) expanding northwestwards, spreading Rutara language and culture ( and assimilating many of the previous Central Sudanic peoples like the Madi in the process[5]) into the Graslands of western Uganda and eastern Democratic Republic of Congo, regions that would one day become Bunyoro, Nkore, Mpororo, etc.
This movement of ideas and practices is likely to have marked the inception of the eras of the Batembuzi and Bacwezi, a period only dimly and fabulously remembered in the later oral traditions, but one in which the key political ideas and economic structures of the later kingdoms first began to be put into effect.