Phonological generalizations in dyslexia: The phonological grammar may not be impaired

Abstract

Dyslexia is commonly attributed to a phonological deficit, but whether it effectively compromises the phonological grammar or lower level systems is rarely explored. To address this question, we gauge the sensitivity of dyslexics to grammatical phonological restrictions on spoken onset clusters (e.g., bl in block). Across languages, certain onsets are preferred to others (e.g., blif ≻ bnif ≻ bdif, where ≻ indicates a preference). Here, we show that dyslexic participants (adult native speakers of Hebrew) are fully sensitive to these phonological restrictions, and they extend them irrespective of whether the onsets are attested in their language (e.g., bnif vs. bdif) or unattested (e.g., mlif vs. mdif). Dyslexics, however, showed reduced sensitivity to phonetic contrasts (e.g., blif vs. belif; ba vs. pa). Together, these results suggest that the known difficulties of dyslexics in speech processing could emanate not from the phonological grammar, but rather from lower level impairments to acoustic/phonetic encoding, lexical storage, and retrieval.

Language universals at birth

“…These results suggest that a precursor of the universal sonority-related preferences seen in adults (12)(13)(14)(15)(16)(17)(18) is present close to birth.…”

“…This phenomenon has been documented in numerous languages with both isolated syllables [e.g., English (12)(13)(14), French (15), Hebrew (16), Korean (17)] and continuous artificial speech (18). Crucially, these effects occur even if the specific syllables under investigation are unattested in the native language of participants (12)(13)(14)(15)(16)(17)(18). These findings open up the possibility that the SSP might not be induced from linguistic experience.…”

Role of the motor system in language knowledge

“…First, our past research has shown that sensitivity to the syllable hierarchy is found with printed materials (i.e., in the absence of any auditory input) (5,30). Conversely, demonstrable damage to the auditory/phonetic systems does not attenuate the sensitivity of dyslexic individuals to the syllable hierarchy (31). Other evidence against the auditory/phonetic explanation is provided by the fact that, when it comes to the phonetic categorization of individual sounds, it is the unfamiliar (i.e., nonnative) (28,(32)(33)(34) or degraded (i.e., masked by noise) (35) sounds that are most likely to engage the motor system.…”

Language Universals Engage Broca's Area

“…These misidentifications are documented irrespective of whether the syllables are present [15] or absent in participants' language[9], [11]–[14], and even when auditory pressures are minimized (e.g., by using printed materials[11], [12]). These results imply an abstract grammatical process that repairs ill-formed syllables as better formed ones (e.g., lbif → lebif )—the worse formed the syllable, the more likely its repair, hence its misidentification.…”