Much research has been conducted in adult second language learning through interaction, but knowledge about the child language learner has remained scarce. To address social language development in middle childhood, the article presents a longitudinal case study concerning a nine-year-old L1 Russian-speaking learner of Finnish. The data consist of 48 h of video-recorded lessons. By examining requests, the article demonstrates how a learner's actions built on interaction, the affordances of the local context and embodiment, and access to multiple languages identifiable as Russian, English, and Finnish. The analysis focuses on the very beginning of language learning and the middle of the academic year. Through a detailed analysis of multimodal interaction, the study demonstrates the progress from simple language such as free-standing nouns and adjectives to more complex language in actions such as requests constructed as clauses by the focal learner. In addition, the analysis enhances understanding of the development of multilingual competence in interaction. Finally, the results indicate that learning a language is intertwined with embodied interactional competence and growth in linguistic repertoires.