In this study we argue that a focus on language learning ecologies, that is, situations for participation in various communicative practices, can shed light on the intricate processes through which minority children develop or are constrained from acquiring cultural and linguistic competencies (here, of a majority language). The analysis draws on a language socialization approach to examine the micro-level contexts of an immigrant child's preschool interactions with peers and teachers, and the interplay between these and macro-level language and educational policies. It was found that, in contrast to institutional and curricular policy aspirations concerning the positive potentials of children's play as a site associated with core learning affordances, the language learning ecology created in the multilingual peer group interactions was limited. Social relations in the peer group, the novice's marginal social position, and the child's rudimentary knowledge of the lingua franca, Swedish, precluded her from gaining access to shared peer play activities. The current study thus corroborates prior research showing that peer interactions in second language settings may pose a challenge to children who have not already achieved some competence in the majority language and that more support and interactions with the teachers can be useful.