This article bridges research to practice by summarizing an interactive content‐enriched shared book reading approach that Spanish‐speaking parents of preschool‐age children can easily use in the home to accelerate content vocabulary knowledge in Spanish. The approach was implemented in preschool classrooms using a transitional bilingual education model in Central Texas and in a Saturday Spanish heritage language school in the Midwestern United States. Spanish‐speaking emergent bilingual children from both lower and higher socioeconomic status backgrounds learned content‐related vocabulary via parent–child discussions of Spanish storybooks and informational texts organized by compelling science and social studies themes and topics. The authors provide recommendations for how teachers can support Spanish‐speaking parents' ability to develop informal knowledge‐building experiences through home‐based interactive book discussions in Spanish.