Inspired by research in language play and linguistic ethnography, this article examines children's language play in early childhood education and care (ECEC) as a locally situated generic practice created through children's semiotic repertoires. The article is based on video-recorded linguistic ethnographic fieldwork in a Danish day care centre. By analysing two play sequences with 3-4 year old children, we examine how the children align to each other in an improvised way while co-creating social worlds. The multimodal micro-ethnographic analysis reveals how an assemblage of chunks of language, musicality, movements, affect and materiality is constitutive of children's language play, and how language play appears as an integral part of children's local language practices. The children's use of a broad range of semiotic repertoires in language play represents a unique practice that might enhance our theoretical and empirical understanding of child language. We argue that empirical insight into children's language play has the potential for developing paths to language and literacy that challenge the often highly prioritised 'precursors to literacy' strategy as the central aim for language learning in ECEC.