Phonology and phonetics dissociate in dyslexia: evidence from adult English speakers

Abstract

ABSTRACTIndividuals with dyslexia exhibit subtle impairments in speech processing. Informed by these findings, a large literature has attributed dyslexia to a phonological deficit. Phonology, however, is only one of many systems engaged in speech processing. Accordingly, the speech perception deficit is consistent with any of multiple loci, including both the phonological grammar and lower level systems – auditory and phonetic. Our present research seeks to dissociate these possibilities. To gauge phonological competence, we examined the sensitivity of adults with dyslexia, native speakers of English, to putatively universal grammatical restrictions on syllable structure. Phonetic processing was examined using standard phonetic identification and discrimination tasks. Across all experiments, participants with dyslexia exhibited multiple phonetic difficulties, while their sensitivity to grammatical phonological structure was intact. These results demonstrate a dissociation between the functioning of the phonetic and phonological systems in dyslexia. Contrary to the phonological hypothesis, the phonological grammar appears to be spared.