The article presents a classroom-based study that engaged linguistically diverse preschool and early school-age children in illustrating books, jointly composing written narratives to accompany their illustrations, and enacting these child-authored books through shared sociodramatic play. Findings from story retell tasks show significant improvement in children's narrative language: vocabulary, syntax, accuracy, and text structure. Analysis of collaborative dialogue during book-making highlights the role of peer and teacher scaffolding in supporting children's literate language and identity development. The article presents an engaging play-based approach for ECE educators to (1) significantly and equitably increase child-led literate language interactions; (2) improve early writing instruction, by increasing meaningful composing experience; (3) strengthen culturally sustaining home/community–school partnerships, through authentic dialogue with caregivers about children's writing; and (4) harness the social and multimodal power of play to promote a range of important early learning goals. (author abstract)