Late Talkers' Language, Metaphor, Theory of Mind, and Reading Skills at 9 Years of Age.

Purpose: Prior work has found that "late talkers" (LTs) as a group continue to demonstrate lower language and reading outcomes compared to their typically developing (TD) peers even into young adulthood. Others identified that children diagnosed with developmental language disorder (DLD) show difficulties later with theory of mind (ToM) tasks and metaphor comprehension, but there is a shortage of research specifically investigating these advanced skills in LTs. The current study therefore compared language-related skills of former LTs with their TD peers at school age.

Method: A longitudinal sample (N = 35) of monolingual German-speaking children was observed from age 1 until 9, comprising TD children (n = 27) and children identified as LTs at age 2 (n = 8), of which two met criteria for DLD between ages 3 and 6. Children's language (productive vocabulary, productive and receptive grammar), reading, metaphor comprehension, and ToM skills (ToM scale and Strange Stories) were investigated, and group comparisons were conducted.

Results: Former LTs performed worse than the TD children on measures of productive vocabulary, receptive grammar, metaphor comprehension, and the ToM Strange Stories task at the age of 9, but not on measures of productive grammar, reading, or the ToM scale.

Conclusions: The findings indicate that LTs can catch up with their TD peers in some areas of language and ToM but that subtle differences remain across other complex areas. Further research is needed to pinpoint possible explanations for why certain skills are more strongly impacted and the potential developmental interactions between these competencies.