The study reported in this article investigates the development of sociolinguistic competence among second-year (US university-level) L2 learners of French who were given systematic instruction on sociolinguistic variation as part of their normal coursework. We focus on the variable use of the negative morpheme "ne" in verbal negation. Drawing from learners' explanations of "ne" presence versus absence, their analyses of two texts representing different levels of discourse, and their own small-group inter-learner online chat discussions, we examine the link between conceptual understanding of variation in French and these learners' development of conscious control over variation. We show that properly organized pedagogical activity can help learners to develop their understanding of variable features of discourse, which ultimately leads (to) the development of their performance abilities. We present both quantitative and qualitative analyses of learners' performance to illustrate their developing control over variation in French, which begins to emerge as a sociolinguistic resource by the end of the academic term.