The Processing of Inflectional Morphology: A Comparison of Children with and without Dyslexia

Children aged 11–12 years with a diagnosis of dyslexia (DR) were compared to chronological and reading-age matched poor readers (PR), and two normal reader groups, age-matched (CA) and spelling and reading-age matched (SA–RA), on their processing of inflectional morphology. In comparison to SA–RAs and PRs, the DRs made more spelling errors on regular past tense verb endings relative to irregular past tense verbs and non-verbs. In reading, the DRs took longer than the other groups to make decisions in the written but not oral condition of a tense judgement task. In addition, they were less affected than the PR and SA–RA groups by case altered disruption to the morpheme boundary of inflected verbs. The findings suggest dyslexic children do not show deficits in morphological processing in spoken language, but they are slower at reading and less accurate at spelling regularly inflected verbs compared with normally developing younger children. This difference could plausibly be accommodated within the Phonological Deficit Hypothesis of dyslexia.