Associations Between Language, Speech Sound, and Learning Disorders

Background and Objectives: Children with specific learning disorders (SLD) often present a history of speech and language deficits. However, systematic evidence on the co-occurrence among distinct learning and communication disorders remains limited. This study aimed to describe the associations among reading, spelling, and math disorders and their relationships with clinically diagnosed speech sound and language disorders and speech sound disorders in a large, well-characterized clinical sample. Methods: 235 3rd- to 8th-grade Italian children with SLD participated in the study. They were categorized in terms of learning (reading, spelling, and math) and comorbid communication disorders (speech sound, and language disorders), according to established diagnostic criteria. Prevalence rates were assessed for each of the resulting subgroups. Results: Comorbidity between the three learning disorders was very frequent; 75.4% of children showed different forms of multiple SLDs, with 47.7% presenting a combined reading, spelling, and math disorder. Communication disorders were reported in 40.4% of the sample. Both language and speech sound disorders frequently co-occurred with spelling disorders, whereas associations with isolated reading or math disorders were more infrequent. Additionally, speech sound disorders frequently co-occurred with isolated spelling disorders, whereas language disorders frequently co-occurred with comorbid spelling disorders. Conclusions: Consistent with previous evidence, the study shows that learning disorders are highly comorbid with communication disorders. Critically, speech and language disorders are most frequently comorbid with spelling disorder, independent of reading and math deficits, highlighting spelling as a potential key interface between phonology, language, and learning.