What should be kept in mind with regard to "tribe" is the whole question of
translation. "Tribes" do not always think or talk of themselves in the
vernacular as "tribes"-the word comes out in translation, or in various forms
of colonial or post-colonial discourse. Hence you have a post-colonial
subliminal force at work.
Of course the word has now passed into everyday use, by both academics and the
general public so the whole thing is very much blended into language. But that
does not mean that people refer to themselves as members of "tribes". More
often it comes up about considerations of status, power etc. e.g. as in
KwaZulu-Natal.