This paper reports on the first stage of a research project that investigates the dynamics of multilingualism and the teaching and learning of mathematics in junior secondary classrooms in South Africa. The paper situates the project theoretically and methodologically and then focusses on an initial set of in-depth interviews with six teachers in three different classroom contexts. The analysis of presences and silences within and across teachers’ accounts suggest that teachers in multilingual contexts confront and produce language-related dilemmas and a paradox as they manage their teaching. These, in turn, raise interesting questions for further analysis and research.