The chapter is a theoretical discussion of the concept of personal repertoire and its application in the context of applied linguistics, particularly in the study of language learning and development. It questions conceptualisations that understand language learning as acquisition of abstract, decontextual and disembodied language knowledge and argues that learners’ know-how is not based on any kind of ‘mental grammar’, but on a personal repertoire of different multimodal semiotic resources. Bringing together ‘old’ and ‘new’ arguments for materialism, personal repertoires are examined focussing on how embodied agentive activity is intertwined with the socially structured environments and their specific material features, tools and artefacts...