A core element of student-teacher partnerships, a form of student participation, is their dialogical nature. However, little research attention has been paid to communication in this context. Therefore, this study aims to gain an in-depth understanding of their deliberative communication patterns. Seventeen deliberative episodes, derived from two cases where students and teachers collaboratively participated in a year-long inquiry project, were subjected to a two-stage analysis: a within-case analysis to determine the structure, function, features, and content of each unit of deliberation, and a cross-case analysis to iteratively compare both cases. The study reveals that in these deliberative discussions: (1) students and teachers frequently and equally formulate substantive contributions or arguments, (2) they adopt four argumentative strategies: construction, confirmation, problematisation and regulation, (3) alternating use of the different argumentative strategies leads to more substantive and candid discussions, and (4) there is a need for moderating interventions. These findings call for reflection on the teachers' role when partnering, more specifically on how to facilitate deliberative communication without compromising on the authenticity between teachers and students.