Final Report Summary - BILITERACY (Bi-literacy: Learning to read in L1 and in L2)
Learning to read is probably one of the most exciting discoveries in our life. Acquiring this unique human cognitive ability not only opens a new world of opportunities, but also changes our brain. Additional brain changes also occur when learning to read in a second language. We investigated how the human brain responds to two major challenges with specific attention to individual differences and reading disabilities. First, the challenge of instantiating a complex cognitive function for which there is no genetic blueprint (learning to read in a first language, L1), and second, the challenge of accommodating to new statistical regularities when learning to read in a second language (L2).
Our findings revealed that (1) learning to read implies an important brain reorganization in the circuits supporting language and vision, so that literacy acquisition changes brain mechanisms for object recognition and spoken language to accommodate visual word recognition; (2) the impact of bilingualism on literacy acquisition does not manifest similarly across bilingual populations because it depends on the specific combination of the languages learned, that will come with different blends of orthographic transparency; (3) the neural modulation of the ventral and dorsal networks depends on transparency of the orthography and reading demands in bilinguals; (4) developmental dyslexia is associated with an atypical sampling of the speech prosodic information that originates in the right auditory cortex, and causes impaired fine-grain phonemic analysis in higher order language processing regions in the left hemisphere (i.e. left inferior frontal gyrus), so that, the impaired perception of speech sounds (prosodic, syllabic and phonemic cues) in dyslexia affects phonological processing needed for learning to read. (5) developmental dyslexia is also associated with differences in subcortical structures and fasciculi engaged in low-level visual processing.
Our findings revealed that (1) learning to read implies an important brain reorganization in the circuits supporting language and vision, so that literacy acquisition changes brain mechanisms for object recognition and spoken language to accommodate visual word recognition; (2) the impact of bilingualism on literacy acquisition does not manifest similarly across bilingual populations because it depends on the specific combination of the languages learned, that will come with different blends of orthographic transparency; (3) the neural modulation of the ventral and dorsal networks depends on transparency of the orthography and reading demands in bilinguals; (4) developmental dyslexia is associated with an atypical sampling of the speech prosodic information that originates in the right auditory cortex, and causes impaired fine-grain phonemic analysis in higher order language processing regions in the left hemisphere (i.e. left inferior frontal gyrus), so that, the impaired perception of speech sounds (prosodic, syllabic and phonemic cues) in dyslexia affects phonological processing needed for learning to read. (5) developmental dyslexia is also associated with differences in subcortical structures and fasciculi engaged in low-level visual processing.