Parallels between the reading and spelling deficits of two subgroups of developmental dyslexics

The spelling errors of third graders who fit phonological and surface profi les of developmental dyslexia were analyzed, along with the errors of young er (reading level matched) and chronologically age matched non-dyslexic com parison groups. In Study 1, errors were analyzed as phonologically constrai ned, unconstrained, or inaccurate and as either orthographically acceptable or unacceptable. Study 2 extended the error classification system to nonwo rd spellings. The main finding was that different types of dyslexics produc ed different types of errors. Both studies found that children produced spe lling errors consistent with their type of dyslexia. The phonological group showed poor knowledge of phoneme-grapheme correspondences, consistent with the existence of a phonological deficit. The surface group's spelling erro r profile differed from the phonological group and closely resembled the yo unger normal comparison group. This pattern is consistent with other eviden ce that surface dyslexia represents a general delay in acquiring literacy s kills. The studies provide converging evidence, from a spelling task, that developmental dyslexia is a non-homogeneous category consisting of at least two major subtypes with distinct etiologies and behavioral sequelae.