Collaborative dialogue contributes to second language acquisition (Ahmadian et Tajabadi, 2020; Mackey, 2012; Payant et Maatouk, 2022), particularly during interactive writing tasks where students are encouraged to collaborate before, during, or after writing a text. This article summarizes the main findings from a series of three studies involving three second language (L2) French classes at a university in Montreal, where each class worked with a partner at different stages of the writing process: either during interactive planning, collaborative writing, or interactive revision. These studies investigated what students talk about during collaborative writing tasks (and in what language) to know if these discussions impact their subsequent writing, and also to understand how students' perceptions affect their engagement in these discussions. The findings from these studies demonstrated the contribution of interactive planning to the development of language skills and highlighted the role of English as an additional linguistic resource. Additionally, findings showed that students with more positive attitudes toward interactive tasks engaged more deeply in metalinguistic discussions. The synthesis of these studies offers practical applications for second language teachers.