Background: Previous research has shown a relationship between speech perception and dyslexia in alphabetic writing. In these studies speech perception was measured using phonemes, a prominent feature of alphabetic languages. Given the primary importance of lexical tone in Chinese language processing, we tested the extent to which lexical tone and aspiration, two fundamental dimensions of Cantonese speech not represented in writing, would distinguish dyslexic from non-dyslexic 8-year-old Chinese children. Tone and aspiration were tested in addition to other phonological processing skills across groups to determine the importance of different aspects of phonological sensitivity in relation to reading disability.
Methods: Dyslexic children and age-matched and reading-level controls were tested on their categorical perception of minimal pairs contrasting in tone and aspiration, phonological awareness, rapid digit naming, and Chinese reading abilities.
Results: While performing similarly to reading-level controls, dyslexic children perceived tone and aspiration contrasts less categorically and accurately than age-matched controls. They also performed more poorly than the age-matched controls on rapid digit naming and a measure of phonological awareness testing children's sensitivity to different grain size units.
Conclusions: Dyslexia in non-alphabetic Chinese correlates with the categorical organization and accuracy of Cantonese speech perception, along the tone and aspiration dimensions. This association with reading is mediated by its association with phonological awareness. Therefore, dyslexia is universally at least partly a function of basic speech and phonological processes independent of whether the speech dimensions in question are coded in writing.