In this paper, we investigate the processes by which groups of primary and secondary school students from two Francophone contexts (Guadeloupe and Québec) try to establish what has been mutually understood (grounding processes) with respect to shared tasks in geography and in literature. We identify the dynamic interplay of meaning-making in dialogue, the knowledge-building processes, and the types of contributions that are made. Analysed data include two videoconference interaction sequences (4 and 13 min) concerning Geothermal Energy and Traditional Folktales, with students at different educational levels. Findings show that interactive confrontation of alternative contexts, that differ in terms of geology (the way that geothermal energy is made) and the status of folktales (oral and written traditions) can lead to misunderstandings due to the overgeneralization of one context to another. Overcoming misunderstandings by grounding leads to the co-elaboration of knowledge on the object of study, the students own context, and the context that they are confronted with. The study emphasizes the importance of interaction strategies that support or inhibit further discussion to deepen reasoning, resolve potential conflict, and reach common knowledge. We discuss implications for the design of productive intercultural collaborative learning situations.