Abstract : To date, the notion of Language Representation (LR) represents a major theoretical challenge for sociolinguistics. Though the prime focus in the domain has been on the variational dimension of language productions, it has also been observed that the analysis of language dynamics can not be limited to the study of language practice: the shared social knowledge that speakers have about their mother tongue is essential for the way a given social group deals with the heterogeneous nature of its language environment. The work undertaken in this realm proposes to specifically approach LR from a sociolinguistic point of view, both on theoretical and methodological grounds: what is LR? How can it be observed and described? Based on a study of the representation of multilingualism in two peripheral French-speaking communities, we will investigate the representational variations in form and content as well as the constraints which underlie these variations. We will more specifically focus on the institutional side of the management of a language environment, in terms of type of language policy: can a given type of policy affect a community's LR? Conversely, can the efficiency of a given language policy be affected by LR? While this study aspires to be part of fundamental research into the functioning of language representations, it also has an applied side, in that it generates results which may contribute to shed some light on the decisional choices made in the context of public language policies.