This article argues for the relevance of biographical approaches to the exploration of the linguistic repertoire. Foregrounding a subject perspective which is seen as a necessary complement to the outside perspective of traditional interactional approaches, it accounts for the multidimensional and diachronic constitution of the linguistic repertoire. The analysis of two different biographical productions, a language biography elicited in a research interview and a published literary text, casts light on the fact that a linguistic repertoire is also determined by the linguistic resources one does not have. The final part of the article considers potential implications for second language learning and teaching.