Sensitivity to Semantic Relationships in U.S. Monolingual English-Speaking Typical Talkers and Late Talkers.

Purpose: Late talkers (LTs) are a group of children who exhibit delays in lan- guage development without a known cause. Although a hallmark of LTs is a reduced expressive vocabulary, little is known about LTs’ processing of seman- tic relations among words in their emerging vocabularies. This study uses an eye-tracking task to compare 2-year-old LTs’ and typical talkers’ (TTs’) sensitiv- ity to semantic relationships among early acquired words. Method: U.S. monolingual English-speaking LTs (n = 21) and TTs (n = 24) com- pleted a looking-while-listening task in which they viewed two images on a screen (e.g., a shirt and a pizza), while they heard words that referred to one of the images (e.g., Look! Shirt!; target-present condition) or a semantically related item (e.g., Look! Hat!; target-absent condition). Children’s eye movements (i.e., looks to the target) were monitored to assess their sensitivity to these semantic relationships. Results: Both LTs and TTs looked longer at the semantically related image than the unrelated image on target-absent trials, demonstrating sensitivity to the taxonomic relationships used in the experiment. There was no significant group difference between LTs and TTs. Both groups also looked more to the target in the target-present condition than in the target-absent condition. Conclusions: These results reveal that, despite possessing smaller expressive vocabularies, LTs have encoded semantic relationships in their receptive vocab- ularies and activate these during real-time language comprehension. This study furthers our understanding of LTs’ emerging linguistic systems and language processing skills. [ABSTRACT FROM AUTHOR]