1. Negative forms in b are widespread in Nilo-Saharan and Afro-Asiatic languages.

2. In a more general sense, the Nilotic peoples include all descendants of the original Nilo-Saharan speakers.

3. Across languages, obviation almost always involves the third person (although second-person obviation is reported for some Nilo-Saharan languages), and the direct–inverse alternation is usually presented as being a way of marking the proximate–obviative distinction between two (or more) third person arguments of a sentence.