This article discusses a sociocultural usage-based perspective on the development of sociolinguistic competence. Previous research has focused on learners' acquisition and use of alternative ways of 'saying the same thing' (i.e. native-like variation) in relation to study abroad, contact with native speakers, and pedagogy. Missing from the literature are studies examining the developmental trajectories of individual learners from a qualitative perspective. This article takes a first step in this direction by documenting the specific lexicogrammatical constructions deployed by one learner of French, Leon, over the course of a 6-week stylistic variation intervention. The findings show that his sociolinguistic repertoire emerged from a single multiword expression, which in combination with Leon's application of new metalinguistic knowledge and mediation from a teacher expanded to become a more productive schematic template. The research suggests that future work on L2 sociolinguistic development would do well to focus on qualitative accounts of individual developmental trajectories, emphasizing the specific lexicogrammatical constructions learners appropriate, to understand how L2 sociolinguistic repertoires are constructed across time.