This is an extended case study on Tanzania highlighting the latest theoretical and methodological approaches in sociolinguistics. A study of the politicization and incorporation of Swahili in the nation-building efforts associated with the introduction of the socialist Ujamaa ideology in 1967. The text focuses on the influence of Ujamaa ideology on Swahili’s formation, treatment, and implementation. It merges macro- and micro-sociolinguistic approaches, as well as historiographic and political-analytic research, contributing to the study of African political ideologies and to research on the continuity between colonial and postcolonial language policies. It makes substantial points about the study of African political ideologies, on the continuity between colonial and postcolonial language policies and on the dispersed nature of language policies over a number of critical actors in society - destereotyping language policy as purely the study of policy makers’ decisions. It includes a new chapter on enregistering the nation. It features updates to the discussions of code-switching and language policies and ideologies.It provides a theoretically rich discussion of language and ideology in Tanzania.