Parental language input is a key predictor of child language achievement. Parentese is a widely used style of child-directed speech (CDS) distinguished by a higher pitch and larger pitch range. A recent parent coaching randomized control trial (Parentese-RCT) demonstrated that English-speaking US parents who were coached to use parentese with…

We introduce a novel method to test a classic idea in developmental science that children's attention to a stimulus is driven by how much they can learn from it. Preschoolers (4-6 years, M=4.6) watched a video where a distracting animation accompanied static, page-by-page illustrations of a storybook. The audio narration for each storybook page…

In urban, industrialized cultures, the best predictor of how children acquire their native language is child-directed speech from adults. However, in many societies, children are much less exposed to such input. What has remained unexplored is the impact of another type of input: other children's speech. In cross-cultural head-turn experiments, we…

Previous research shows that infants of parents who are more likely to engage in socially contingent interactions with them tend to have larger vocabularies. An open question is "how" social contingency facilitates vocabulary growth. One possibility is that parents who speak in response to their infants more often produce larger…

Children learn language by listening to speech from caregivers around them. However, the type and quantity of speech input that children are exposed to change throughout early childhood in ways that are poorly understood due to the small samples (few participants, limited hours of observation) typically available in developmental psychology. Here…

There is substantial evidence that children's apparent omission of grammatical morphemes in utterances such as "She play tennis" and "Mummy eating" is in fact errors of commission in which contextually licensed unmarked forms encountered in the input are reproduced in a context-blind fashion. So how do children stop making such…

What is vision's role in driving early word production? To answer this, we assessed parent-report vocabulary questionnaires administered to congenitally blind children (N = 40, Mean age = 24 months [R: 7-57 months]) and compared the size and contents of their productive vocabulary to those of a large normative sample of sighted children (N =…

Infants are immersed in a world of sounds from the moment their auditory system becomes functional, and experience with the auditory world shapes how their brain processes sounds in their environment. Across cultures, speech and music are two dominant auditory signals in infants' daily lives. Decades of research have repeatedly shown that both…

It is known that the rhythms of speech are visible on the face, accurately mirroring changes in the vocal tract. These low-frequency visual temporal movements are tightly correlated with speech output, and both visual speech (e.g., mouth motion) and the acoustic speech amplitude envelope entrain neural oscillations. Low-frequency visual temporal…

Recent evidence suggests that deaf children with CIs exposed to nonnative sign language from hearing parents can attain age-appropriate vocabularies in both sign and spoken language. It remains to be explored whether deaf children with CIs who are exposed to early nonnative sign language, but only up to implantation, also benefit from this input…