Reading processes in L1 and L2 among dyslexic as compared to regular bilingual readers: Behavioral and electrophysiological evidence

The present study examined differences between 'regular' and dyslexic adult bilingual readers when processing reading and reading related skills in their first (L1 Hebrew) and second (L2 English) languages. Brain activity during reading Hebrew and English words and pseudowords was studied using behavioral and ERP measures. Results indicated discrepancies in the processing profiles of dyslexic and regular bilinguals in both first and second languages. In general, dyslexic readers were significantly slower and less accurate compared to regular readers during processing of information in both L1 and L2. Furthermore, the latencies of the evoked potentials were later among dyslexic readers at all levels of the cognitive processing sequence in both languages, but were more pronounced in English (L2). In contrast, regular readers displayed either similar or significantly shorter ERP latencies in English compared to Hebrew on most of the experimental tasks. The data from the present study supports both the 'Central Defic it' and 'Script Dependent' Hypotheses by demonstrating universal deficits in L1 and L2 among dyslexic readers along with differential manifestations of these deficits as a function of specific orthographic features. The present results are also in line with the 'Dyslexic Automatization Deficit Hypothesis' which purports automatization deficits as a more general and more pervasive cause underlying dyslexic performance. Unlike dyslexic readers, regular bilingual readers not only have the capacity to reach automaticity in their second language, but can also exhibit more effective processing of reading material in English at different levels of the cognitive sequence, despite its irregular nature. Mastery of reading proficiency in English as L2 need not be lower than mastery of Hebrew as L1. Moreover, it may even be higher due to the unique features of the languages and orthographies involved.