How can teachers ascertain the musical knowledge of their secondary school students following collective music productions? In creative music-making tasks, teachers should connect subject specific knowledge with several fields of students’ experience in order to foster music learning. Following previous work about supporting creative collaboration in music education at school, the goal of this study is to observe the techniques teachers use to talk with students in order to identify their knowledge mobilized during a shared creative music-making task inspired by abstract paintings. Video recordings of 29 small groups of students aged from 11 to 15 years old from seven different classes capture two precise moments during the lesson. The first of these moments is that of students presenting their final productions to their classmates and teacher. The second moment is when the teacher talks with his or her students about the composition process and their final creation in relation to the abstract painting. The analysis shows techniques that teachers use in order to talk with students. This study helps to better understand teachers’ needs in order to successfully stimulate music learning in creative musical situations, and shows how different fields of students’ experience are connected to music learning.