LAUSR

For the past 25 years, researchers have investigated language input to children from high- and low-socioeconomic status families. Hart and Risley (1995) first reported a '30 Million Word Gap' between high-SES and low-SES children. More recent studies (e.g., Sperry et al., 2019) have challenged the size or even existence of this gap. The present study is a quantitative meta-analysis on socioeconomic differences in language input to young children, which aims to systematically integrate decades of research on this topic. We analyzed 19 studies and found a significant effect of SES on language input quantity. However, this effect was moderated by the type of language included in language quantity measures: studies that include only child-directed speech in their language measures find a large SES difference, while studies that include all speech in a child's environment find no effect of SES. These results support recent work suggesting that methodological decisions can affect researcher' estimates of the 'word gap.' Overall, we find that young children from low-SES homes heard less child-directed speech than children from mid- to high-SES homes, though this difference was much smaller than Hart & Risley's '30 Million Word Gap.' Finally, we underscore the need for more cross-cultural work on language development and the forces that may contribute to it, highlighting the opportunity for better integration of observational, experimental, and intervention-based  approaches. Research Highlights We conducted a quantitative meta-analysis on language input to young children of different socioeconomic statuses (SES) and analyzed data from 19 studies (nearly 2000 children). The overall effect of SES was statistically significant (g=0.41), but much smaller than the often-cited "30 Million Word Gap." Studies that included only child-directed speech in their language measures found a larger SES difference than those that included all speech in children's environments. This article is protected by copyright. All rights reserved.