Reading different orthographies: an fMRI study of phrase reading in Hindi–English bilinguals

The aim of the present study was to use functional imaging to compare cortical activations involved in reading Hindi and English that differ markedly in terms of their orthographies by a group of late bilinguals, more fluent in Hindi (L1) than English (L2). English is alphabetic and linear, in that vowels and consonants are arranged sequentially. In contrast, Hindi, written in Devanagari, is an alphasyllabary and non-linear writing system wherein vowels are placed around consonants making it a visually complex script. Additionally, the grapheme to phoneme mapping in English is opaque while Devanagari is transparent. Effects of reading fluency were seen in significantly slower reading times and direct English–Hindi comparison showed left putamen activation for the less fluent language (English). Direct Hindi–English orthography comparisons revealed activation in the temporal pole and caudate nucleus of the right hemisphere, cortical areas known to be involved in semantic and visual processing. We also find activation in right superior temporal gyrus, which we attribute to the syllabic rhythm of Hindi. Our results suggest increased visuo-spatial demands for processing Hindi as observed in other visually complex orthographies.