Juan L., L. 1 , Willy, S. 2 , Miguel, L. 1 , Soraya, B. 1 , Almudena, G. 1 , Victoria, R. 1 & Sergio, V. 1
1 Facultad de Psicología, Universidad de Málaga; Málaga, Spain
2 Universidad René Descartes, París, Francia
Previous studies have shown that children suffering from developmental dyslexia have a deficit in categorical perception of speech sounds (Maassen et al., 2001; Serniclaes et al., 2001; Serniclaes et al., 2004; Werker & Tees, 1987). 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, Sprenger-Charolles, Carré, & Démonet, 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. In this study we explored the categorical perception deficit in a Spanish sample (102 dyslexics and a control group of 109 from two schools levels, 7 & 9 yrs). Children identified and discriminated /ba–pa/, /de–te/ and /di–ti/ syllables, along a voice onset time (VOT) continuum. Several kind of categorical perception indexes were calculated. Main results were the following. All the continua showed the classical perception deficit, however the magnitude of the effect was stronger on the the /de-te/ stimuli. In general, Spanish children with dyslexia discriminated among phonemically contrastive pairs less accurately than did chronological age and reading level controls and also showed higher sensitivity in the discrimination of allophonic contrasts, but the latter not reached significant differences. These results are consistent with other studies, suggesting that children with dyslexia perceive speech in a less categorical way.