Children from low-socioeconomic status (SES) families often fall behind their middle-class peers in early language development. But interventions designed to support their language skills are often costly and labor-intensive. This study implements an inexpensive and subtle language intervention aimed at sparking parent-child interaction in a place that families naturally visit: the supermarket. We placed signs encouraging adult-child dialogue in supermarkets serving low- and mid-SES neighborhoods. Using an unobtrusive observational methodology, we tested how these signs affected adult-child interactions. When signs were present in supermarkets serving low-SES neighborhoods, both the amount and the quality of talk between adults and children increased significantly, compared to when the signs were not present; signs had little effect in middle-SES supermarkets. This study demonstrates that implementing simple, cost-effective interventions in everyday environments may bolster children's language development and school readiness skills.