The historical background and the current status of Swahili in Kenya and Tanzania, where it is designated as the national language, and in Uganda, where it has assumed a less prominent role, are described. Major factors contributing to the selection of national languages in the region are presented. The ways both linguistic and sociopolitical features influence a language's viability as the national language, especially in a heavily multilingual, multicultural setting are analyzed. The discussion focuses on the ongoing competition between languages in different domains and the complexity of language choice for individual speakers. Changes occurring in Swahili's internal development and patterns of use are also examined in this context. (MSE)