This paper seeks to explore at least one aspect of interactional practices in two different multilingual mathematics classroom contexts with learners drawn from different socio-cultural backgrounds. The data collection strategies for this ethnographic study of multi-age primary multilingual mathematics classrooms (with learners aged 12-14) in the EC (Eastern Cape) province of SA (South Africa) included classroom observations, audio-recordings, video tapes and field notes. This study is framed by communicative and socio-cultural perspective (Lemke, 1995; Vygotsky, 1987) for analyzing dialogical interactions in these classes. The results of this study raise awareness of how some pedagogical practices of classroom engagement could be socially predetermined to serve as contributory factors of either effective or ineffective participation in classroom dialogue. Utterance is seen as the basic unit of analysis, and the triadic view implies that the pattern, content and the use of the utterance are mutual, reciprocal and hence triadic. In brief, the findings of this study indicate that even the dominating discourse structure has the form of a triadic dialogue, classrooms can be places in which knowledge is dialogically co-constructed.