Word learning and verbal working memory in children with developmental language disorder

Area of Science:

• Child language acquisition
• Developmental language disorder (DLD)
• Neurodevelopmental disorders

Background:

• Children with DLD face challenges in learning word forms and meanings, not form-referent links.
• Impaired encoding, not retention, is implicated in DLD word learning difficulties.
• Verbal working memory may influence word learning skills in DLD.

Purpose of the Study:

• To investigate word learning over several days in children with DLD.
• To confirm if encoding, not retention, is problematic for DLD word learning.
• To explore the role of verbal working memory in DLD word learning.

Main Methods:

• A four-day word learning protocol was used with 50 children with DLD and 54 typically developing (TD) children.
• Encoding was assessed on Day 1, re-encoding on Days 2-3, and retention on Day 4.
• Word learning was evaluated via Naming, Recognition, Description, and Identification tasks.

Main Results:

• Children with DLD showed intact form-referent link learning (Identification) but impaired learning of word forms (Naming, Recognition) and meanings (Description).
• DLD deficits were evident in initial encoding and re-encoding, though learning rates were similar to TD children.
• Verbal working memory significantly moderated word form learning, with lower accuracy in DLD children with poor verbal working memory.

Conclusions:

• Children with DLD exhibit difficulties in learning novel word forms and meanings, but not form-referent links.
• Word learning deficits in DLD appear linked to encoding issues, though retention warrants further study.
• Impaired word form learning in DLD may be specific to individuals with low verbal working memory.