This study investigates the influence of semantic maturation on early lexical development by examining the impact of contextual diversity--known to influence semantic development--on word promotion from receptive to productive vocabularies (i.e., comprehension-expression gap). Study 1 compares the vocabularies of 3685 American-English-speaking…

This longitudinal study investigated the effects of maternal emotional health concerns, on infants' home language environment, vocalization quantity, and expressive language skills. Mothers and their infants (at 6 and 12 months; 21 mothers with depression and or anxiety and 21 controls) provided day-long home-language recordings. Compared with…

There is little evidence that infants learn from infant-oriented educational videos and television programming. This 4-week longitudinal experiment investigated 15-month-olds' (N = 92) ability to learn American Sign Language signs (e.g., patting head for hat) from at-home viewing of instructional video, either with or without parent support,…

Retrospective studies indicate 2 major classes of autism spectrum disorder (ASD) onset: early and later, after a period of relatively healthy development. This prospective, longitudinal study examined social, language, and motor trajectories in 235 children with and without a sibling with autism, ages 6-36 months. Children were grouped as: ASD…

The concurrent and predictive relations of sensorimotor behavior and play to language in the second year were assessed among 19 preterm and 20 full-term infants tested at 13 1/2 and 22 months of age. Numerous associations between play and language were identified; sensorimotor behavior and language in the same age period were relatively loosely…