Morphological knowledge and spelling in French-speaking adults with developmental dyslexia

Spelling errors are among the most persistent symptoms of dyslexia in adults. This study investigated the influence of morphological information on spelling accuracy in French-speaking adults with developmental dyslexia. Specifically, we aimed to (1) compare university-level adults with dyslexia and age-matched controls in spelling morphologically complex words, and (2) examine the role of morphological awareness in spelling among individuals with dyslexia. In total, 53 adults with dyslexia and 55 typical adult readers completed a spelling task with five types of words: words with silent final letters that were either morphologically predictable or not, suffixed words, prefixed words, and inconsistent monomorphemic words. Additional measures included reading fluency, phonological awareness, morphological awareness, vocabulary, and general spelling. Results showed that adults with dyslexia benefited more than controls from morphologically predictable cues in spelling, particularly for silent final letters. Moreover, morphological awareness predicted spelling in adults with dyslexia, even after controlling for phonological awareness and vocabulary. These findings allow us to better understand the spelling profile of adults with dyslexia at university level.