In this article, the purpose is to re-aim (= look again) the speech of 13-year-old students while solving relational situations that lead to algebraic thinking. For this we use the Semantic Field Model (MCS) to identify elements of mathematical knowledge that prevail in students, when we let them speak freely, asking questions, making conjectures and arguing. The MCS allows us to reflect on the importance of listening and how students' speech and production are legitimated in the process of doing math in the classroom when they face rich and meaningful tasks. The experiences reported here are part of a research project about what has been called a lakatosian-inspired classroom environment (LOPES, 2016). In particular, we are interested in the quality of the scientific / mathematical production of students' speeches in this environment.