Comparative research in multilingual urban primary schools indicates that the pedagogical and political goals of schooling may operate at cross-purposes. Classroom observations and teacher interview-discussions were conducted in classes for immigrant children in Montreal, Quebec, Canada, where the language of instruction is French, and in classes in Pretoria, Gauteng Province, South Africa, where children from many different language backgrounds are taught in English. Two main themes emerged: (1) pedagogically, effective teacher-learner communication can break down when teachers are unaware of the roles that language and culture play in second language classrooms; (2) politically, efforts to assimilate learners into new socio-cultural/political contexts sometimes take precedence over sound pedagogical practice, such as drawing on the linguistic and cultural repertoire that learners bring to the classroom. This ongoing qualitative research underlines the importance of preparing pre-service and in-service teachers for the linguistic and cultural diversity they are bound to encounter in their classrooms, and of deepening their understanding of the influence of such diversity on the teaching-learning process. (Contains 8 notes.)