[PS-1.7] A longitudinal study on categorical and allophonic perception on dyslexic Spanish readers

Luque, J. L. 1 , López-Zamora, M. 1 , Bordoy, S. 1 & Serniclaes, W. 2

1 Universidad de Málaga (Spain)
2 Université libre de Bruxelles

Previous studies have shown that children suffering from developmental dyslexia have a deficit in categorical perception of speech sounds (Werker & Tees, 1987; Maassen et al., 2001; Serniclaes et al., 2001; Serniclaes et al., 2004). However, the potential theoretical value of the CP deficit only became apparent much more recently when it was shown that dyslexics not only have weaker discrimination between categories but also better discrimination within categories (Serniclaes et al. 2001). The CP deficit would thus reveal an allophonic mode of speech perception, characterized by the use of allophones rather than phonemes. This type of perception could get straightforward consequences during the establishment of grapheme - phoneme correspondences. Conversely, literacy process can drive changes from allophonic to categorical perception (Noordenbos et al., 2012). In this study we explored the evolution of the categorical and allophonic perception deficits in a Spanish sample (102 dyslexics and a control group of 109 from two schools levels, 7 & 9 yrs). In the first phase, children identified and discriminated ba/pa, de/te and di/ti syllables, along a voice onset time (VOT) continuum. All the continua showed the classical perception deficit, i.e. Spanish children with dyslexia discriminated among phonemically contrastive pairs less accurately than did chronological age controls. Children with dyslexia also showed higher sensitivity in the discrimination of allophonic contrasts, but only for one of the three continua under study (ba/pa). These results are consistent with other studies, suggesting that children with dyslexia perceive speech in a less categorical way and also that they exhibit enhanced discrimination of allophonic (subphonemic) contrasts. Second phase results are now being processed and they will be ready to be presented.