The Nature of Phonological Impairments in Dyslexia and Stuttering: Evidence from Phonemic, Semantic, and Design Fluency Tasks

Objectives: Using executive fluency tasks, the current study investigated whether these challenges reflect phonological representations themselves or access to intact representations during self-reported adults who stutter (AWS) and self-reported dyslexic adults.Method: An online, unsupervised sample of 62 self-reported AWS, 62 self-reported dyslexic adults and 62 neurotypical adults completed a modified, typed version of semantic and phonemic fluency, as well as a mouse-drawn version of design fluency. We analyzed switching (shifting between subcategories; proxy for retrieval efficiency) and cluster size (words per subcategory, proxy for representational integrity). Results: Controlling for nonverbal IQ and language measures, hierarchical regression showed that dyslexia and stuttering significantly predicted reduced overall phonemic output, whereas semantic and design fluency remained unaffected. Both groups showed reduced switching, though more pronounced in the dyslexia group. Conversely, only stuttering predicted reduced cluster size.Conclusion: Given the heterogeneity of these neurodivergent profiles, these findings suggest that, in dyslexia, access to phonological representations is affected. Conversely, stuttering affects the representations themselves. For individuals presenting these specific cognitive signatures, interventions could be tailored toward either retrieval strategies or representational strengthening.