This exploratory study aimed to evaluate the spelling of derived words by dyslexic adolescents and to verify whether this is associated with lack of vocabulary and/ or morphological knowledge. A cross-sectional reading level-design was employed in order to determine differences in spelling, derivational morphology and vocabulary tasks between dyslexic students aged 13+ and age-matched and reading level matched control groups. The study confirmed a profound spelling impairment of dyslexic students in comparison with two control groups but this was not associated with poor vocabulary in relation with their age-peers. In contrast, they exhibited lower levels of morphological knowledge than age-matched controls but equivalent with the reading level controls. These results are interpreted in the light of current developmental models of spelling that support a reciprocal interaction between spelling and metamorphology.
- Derivational morphology