When I wrote that dividing Uganda into watertight Nilotic North and Bantu South was not entirely correct, some people sought clarification and elaboration. Earlier on some people had also raised the question whether the people of southern Uganda who are linguistically the same (Bantu-speakers) are also racially (or ethnically) the same.
For Uganda’s northern region one can safely use the Nilotic classification. For Buganda, Bunyoro and Toro one can also safely use the Bantu classification since intermarriage between Nilotic and Bantu peoples was so thorough that new communities emerged, adopted a common Bantu language and practiced mixed farming thereby ending the pastoralist and agricultural specialization between Nilotic and Bantu peoples respectively. However, in south west Uganda (Ntungamo and Rujumbura in particular) the situation is different.
Bantu people who speak Bantu language or Bantu Bantu-speakers (BBS) from Cameroon/Nigeria border arrived in southwest Uganda first through the Congo region. They practiced mixed farming of crops, short horn cattle, goats and sheep and poultry. They also manufactured a wide range of products particularly those based on iron ore. Centuries later, Nilotic Luo-speaking people with long horn cattle arrived in the area. Their ancestors came from southern Sudan. Although the Nilotic people (Bahima and Bahororo) adopted Bantu language, hence Nilotic Bantu-speakers (NBS), culturally and economically they remained distinct from Bantu Bantu-speakers (BBS). Separate identities were retained through a combination of strict restrictions on inter-marriage and specialized economic functions.