This article studies the singular relationship that children, adolescents, parents and professionals have with a language other than their mother tongue. In order to do so, the authors rely on three clinical research experiences: participant observations and clinical interviews with newcomer students and specialized teachers in Germany, professional practice analysis groups dedicated to teachers specialized in the reception of allophone students in France, and discussion groups with children and parents of immigrant origin in Brazil. The problematic focuses on the ambiguities, the ambivalences and the paradoxes specific to the acquisition of the language of the host country for children and teenagers. This learning can indeed structure as well as prevent a process of subjectivation often already weakened by the traumatic ordeals linked to migration. The language of the other reveals itself to be a double place of transition : between first original objects and later investments socialized in another cultural framework, between what is familiar and the strangely other. Under what conditions can this learning of the language of the other preserve the paradox, maintain the original link and bring about new links while risking denying the previous one? In what way and under what circumstances can the language of the other serve as an alibi, as a defensive means against the return of a repressed memory, against the expression of a previous intimate wound, of a questioning of identity of another nature, etc.? These are the questions to which this text tries to bring some analyses.