Becoming a speaker of second language (L2) is intimately linked with socialization ot use languge and the development of interactional competence, including the ability to recognize culturally appropriate affective stances and social identities, and to master communicative norms of language. This socialization involves developing an intricate understanding of cultural practices and ways of acting in a particular community. In many societies, an important setting of children's L2 language socialization is classrooms. This chapter examines L2 socialization practices aimed at teaching vocabulary in swedish at the primary school level. By examining vocabulary teaching practices in the form of vocabulary explanations, it will show how these practices serve as a crucial site for learning words together with their cultural meanings in the majority language, swedish. The teaching of vocabulary is discussed here as a prime example of socialization to use language (as social action) and socialization through the use of language.