This paper presents results from an ethnographic study of language policy as it is enacted in everyday interaction in two language profile preschools in Sweden with explicit monolingual language policies: English and Finnish, respectively. However, in both preschools, children are free to choose language or code alternate. The study shows how children through their interactive choices create and modify language policy-in-practice. We analyze extracts from typical free play interactions in each setting. We show how children use code alternation as a contextualization cue in both settings, but with somewhat different interactional consequences. Children in both preschools tend to follow the lead of the preceding speaker's language choice. Code alternation is also a means to manage conversational roles, for example, to show alignment. While the staff give priority to the profile language, the children show through their interaction that skills in both the preschool's profile language and in Swedish are valuable.