Can early childhood education (ECE) support the societal language development of children from linguistically diverse backgrounds? This study examined how existing variation in classroom interaction quality (CLASS Pre-K), classroom composition (percentages of children from low-income backgrounds and dual language learners [DLLs]), and duration of attending German ECE were related to language trajectories from 30 to 73 months of age (n = 519 children in 154 classrooms). DLL status served as a focal moderator and parental education was considered as an additional moderator. Age-based growth models revealed interactions between DLL status and ECE characteristics. There were numerous intercept effects that endured over the age span studied. Interaction quality (emotional support) and classroom composition (percentage of DLLs) were related only to DLLs' German language growth. Parental education did not moderate ECE effects. Hence, the observed range of variation in German ECE may matter for DLLs' societal language development but may be of less relevance for monolingual children.