"Functional Multilingual Learning" ("FML") aims to leverage pupils' full language repertoire in a strategic and transversal way across the curriculum in order to enhance access to conceptual understanding and improve skills in the language of schooling. This linguistic-ethnographic study explores the pedagogical decisions of four teachers in a French-speaking primary school in Brussels, Belgium as they create 'meaningful multilingual tasks' for their linguistically diverse classrooms. Findings indicate that tasks serving symbolic and linguistic functions were the easiest for teachers to conceptualise, and that class-level learning objectives often took precedence over individual objectives. Multilingual scaffolding only occurred in classrooms already functioning extensively within a socio-constructivist paradigm and needed to be supported by a free classroom language policy to be the most effective. Whole-class tasks generated a new sense of linguistic capital but entailed a reframing of the notion of inclusion as they sometimes generated feelings of linguistic insecurity or resulted in limited participation.