Two Portuguese children of immigrants were observed over a period of two years within the complex sociolinguistic context of the Luxembourgish multilingual school-system. The data allow the analysis of their relations with the languages they learn at school: Luxembourgish, German, French and Portuguese. The observations focus on the two pupils struggling with the languages of the "legitimate market" and the "islets of liberty" (Bourdieu). Their different strategies lead to opposite results: one manages to cope with the system, the other borders on failure. The theoretical frame of the study is based on socio-cultural theory (Vygotsky, 1962), enhanced by the demands of a multilingual school. The study relies on a qualitative, ethnographically oriented methodology. (Contains 3 notes and 4 figures.)