Through a case study of the mobilisation around the Luxembourgish language in the 1970s and 1980s, this article investigates the paradox of contemporary linguistic nationalism, resulting from a hiatus between the continued influence of the classic nation‐state model and the new constraints linked to a changed socio‐historical context. Based on an analysis of actors' discourses, parliamentary debates and legislative documents, the investigation retraces the social, political and economic dynamics as well as the cognitive mechanisms leading to a change in the social perception of the Luxembourgish language. It shows how the contemporary context implies specific constraints and difficulties for mechanisms of the invention of tradition, but that at the same time the traditional nation‐state model, where one nation equates with one state and one language continues to function as a reference. Through the Luxembourgish case is raised the more general question of the relation between linguistic nationalism, modernity and change in a contemporary context.