Language learning, socioeconomic status, and child-directed speech.

Young children's language experiences and language outcomes are highly variable. Research in recent decades has focused on understanding the extent to which family socioeconomic status (SES) relates to parents' language input to their children and, subsequently, children's language learning. Here, we first review research demonstrating differences in the quantity and quality of language that children hear across low-, mid-, and high-SES groups, but also-and perhaps more importantly-research showing that differences in input and learning also exist within SES groups. Second, in order to better understand the defining features of 'high-quality' input, we highlight findings from laboratory studies examining specific characteristics of the sounds, words, sentences, and social contexts of child-directed speech (CDS) that influence children's learning. Finally, after narrowing in on these particular features of CDS, we broaden our discussion by considering family and community factors that may constrain parents' ability to participate in high-quality interactions with their young children. A unification of research on SES and CDS will facilitate a more complete understanding of the specific means by which input shapes learning, as well as generate ideas for crafting policies and programs designed to promote children's language outcomes. WIREs Cogn Sci 2016, 7:264-275. doi: 10.1002/wcs.1393 For further resources related to this article, please visit the WIREs website.