There is an ongoing reform towards more inquiry-based teaching in school curriculum policy in South Africa. Reform towards more inquiry-based approaches is already integrated in pre-service teacher education programmes. As inquiry-based approaches have been gaining momentum worldwide, there is an increasing concern that dialogic interaction in classroom communication is being neglected. This is especially within teacher-orchestrated classroom interactions that should foster greater learner centredness and thus authentic scientific inquiry. In learner-centred teaching approaches, student contributions should be explicitly taken into account as part of classroom interactions in science. Learner-centred approaches provide the rationale for improved interaction, especially when student contributions should be considered within teacher-orchestrated communications. The aim of this study is to bring forth indicators that are connected to different forms of interactions and complement the dialogic-authoritative categorization through in-depth analysis of two lesson transcript examples. Even though over-authoritative and even transmission modes of communication seemed to prevail in South African classrooms, it is through finding building blocks for dialogicity this status can be challenged towards more learner-centred interaction. The explicitness of dialogicity and fundamentally contrasting differences between examples of dialogic and authoritative approaches are presented through the in-depth analysis of classroom interactions of two case episodes. Implications for teaching and teacher education are discussed.