The Kenyan election, wrote Jeffrey Gettleman for the New York Times in his December 31 dispatch from Nairobi, "seems to have tapped into an atavistic vein of tribal tension that always lay beneath the surface in Kenya but until now had not provoked widespread mayhem." Gettleman was not exceptional among those covering the post-election violence in his stress on "tribe." But his terminology was unusually explicit in revealing the assumption that such divisions are rooted in unchanging and presumably primitive identities.
Here's an interesting article: 'Talking about "Tribe": Moving from Stereotypes to Analysis,' Africa Policy Information Center (APIC), November, 1997:
For most people in Western countries, Africa immediately calls up the word "tribe." The idea of tribe is ingrained, powerful, and expected. Few readers question a news story describing an African individual as a tribesman or tribeswoman, or the depiction of an African's motives as tribal. Many Africans themselves use the word "tribe" when speaking or writing in English about community, ethnicity or identity in African states.
Yet today most scholars who study African states and societies--both African and non-African--agree that the idea of tribe promotes misleading stereotypes. The term "tribe" has no consistent meaning. It carries misleading historical and cultural assumptions. It blocks accurate views of African realities. At best, any interpretation of African events that relies on the idea of tribe contributes no understanding of specific issues in specific countries. At worst, it perpetuates the idea that African identities and conflicts are in some way more "primitive" than those in other parts of the world. Such misunderstanding may lead to disastrously inappropriate policies.
In this paper we argue that anyone concerned with truth and accuracy should avoid the term "tribe" in characterizing African ethnic groups or cultures. This is not a matter of political correctness. Nor is it an attempt to deny that cultural identities throughout Africa are powerful, significant and sometimes linked to deadly conflicts. It is simply to say that using the term "tribe" does not contribute to understanding these identities or the conflicts sometimes tied to them. There are, moreover, many less loaded and more helpful alternative words to use. Depending on context, people, ethnic group, nationality, community, village, chiefdom, or kin-group might be appropriate. Whatever the term one uses, it is essential to understand that identities in Africa are as diverse, ambiguous, complex, modern, and changing as anywhere else in the world.