People with profound intellectual and multiple disabilities (PIMD, or polyhandicap in French) are characterized by a combination of profound cognitive disabilities and profound neuro motor dysfunctions (Nakken & Vlaskamp, 2002). This extreme situation entails a strong dependency on others (family, caregivers). Probably at least in part because of that dependency, the potential of these people e.g. in learning situations often remains unnoticed (Detraux, 1987), even though previous research has shown that their socio-emotional skills are mostly preserved, especially when they are in contact with familiar persons (Nader-Grosbois et al., 2008). The ongoing Polyscol study focuses, among other things, on initiatives taken by students with PIMD in a classroom learning context. More precisely, we analyze behaviours spontaneously displayed by these students (i.e., without being explicitly invited to do so) in the classroom. Our first results (e.g., Atlan, Toubert, & Puustinen, 2017) showed the students with PIMD participating in the Polyscol study did express spontaneous behaviours during class time and that their behaviours could be addressed to the teachers or other professionals, peers (i.e., other students with PIMD), and objects. Within this context, the aim of the present paper was to analyze and interpret in more detail the expression of those spontaneous behaviours and their relations with the students’ socio-emotional and socio-cognitive processes. The participants were twenty-three 6 to 15-year-old French students with PIMD, attending five medical educational institutes. During one school year, they attended two one-hour classes per week in their institute. In the classroom, there were a total of four or five students with PIMD and two teachers as well as some other professionals, when necessary. Three randomly selected classes (i.e., one per trimester) were filmed during the school year and analysed with teachers and professionals. Our first analyses focusing on the students’ spontaneous behaviours addressed to the teachers and other professionals have revealed the existence of a large panel of “methods” (e.g., joint attention, imitation, bodily contact, using an object) used by the students with PIMD to initiate social interactions. Those methods or indicators show the necessity to pay attention to very subtle signs or movements in order to fully appreciate the huge variety of behaviours displayed by the students with PIMD. Engagement of the body during those spontaneous behaviours clearly reinforces the learning process. Finally, optimal understanding of the “private language” (Mellier, 2006) of these students necessitates the collaboration of researchers, teachers, caregivers, and families.