Towards understanding dyslexia in a language with transparent orthography Investigation of perceptual and phonological abilities in Telugu native speakers

Abstract

Developmental dyslexia is considered genetic in origin associated with unexpected difficulties in reading writing and comprehension despite normal intelligence and socioeconomic status Its nature and prevalence rate differ across languages These differences gave rise to many debates about its universality and specificity Additionally prevalence estimate of dyslexia in different countries seems to be related to the shallowness of the orthography Telugu is an Akshara based language with a easy mapping between the grapheme and its constituent phoneme and it falls on the coarse transparent level In Telugu phoneme is not the smallest grain size nor the reading instructions phoneme based as in English In that case one can ask how a phoneme deficit could underlie reading difficulties in Telugu Thus we hypothesized that reading difficulties of Telugu native speakers would be perceptual in nature rather than phonological This thesis address the reading difficulties of Telugu native speakers specifically perceptual and phonological deficits Further appropriate intervention methods are devised in this thesis to address specific deficits We conducted a set of perceptual and phonological tests on dyslexic and normal observed significant group differences on perceptual tests but not on the phonological tests The results are in line with other transparent languages We propose a bilingual reading model for Telugu and other Akshara languages The qualitative analysis of the reading errors indicates that there is impairment of the visual letter detector components that lead to peripheral dyslexia and at the sublexical route causing the vowelletter dyslexia among Telugu native speakers These errors are also related to visual and auditory attention deficits Consequently we designed interventions that could assist in improving visual and auditory skills The contributions of the thesis could provide the foundation for devising more accurate diagnostic protocols and offer effective interventions for children with reading difficulties