I wouldn't agree with Peter Limb's statement that 'tribes do not
always think or talk of themselves in the vernacular as "tribes".
They do, but maybe we should say that some tribes don't. It is for
this reason that some African national politics is bedevilled by
`tribalism'.
A good example of a country where tribes talk and think of
themselves as tribes is Uganda: the Baganda are always Baganda first
before they are Ugandans. On the passport application forms there is
a space where applicants have to write down their tribe & name their
ancestors!! If you ask a person from Buganda what his/her origin is
he/she will say that she is a Muganda (a person of the Ganda tribe);
if that person is from Lango (northern Uganda) he/she will also say
that he/she is a Langi etc. It is not a matter of status or power
for most of these people.