The purpose of this research was to investigate issues of both home language (isiXhosa) and the language of learning and teaching, i.e. English, when 9th grade second language learners engage in problem- solving and sense-making of real wor(l)d problems in multilingual mathematics classrooms. In addition, the study also explored whether the introduction of discussion and argumentation techniques in these classrooms can ameliorate these issues. The study used a pre-test - intervention - post-test mixed method design utilising both quantitative and qualitative data. The data collection...