Lexical processing and distributional knowledge in sound-spelling mapping in a consistent orthography: A longitudinal study of reading and spelling in dyslexic and typically developing children

This study examined the ability to master lexical processing and use knowledge of the relative frequency of sound–spelling mappings in both reading and spelling. Twenty-four dyslexic and dysgraphic children and 86 typically developing readers were followed longitudinally in 3rd and 5th grades. Effects of word regularity, word frequency, and probability of sound–spelling mappings were examined in two experimental tasks: (a) spelling to dictation; and (b) orthographic judgment. Dyslexic children showed larger regularity and frequency effects than controls in both tasks. Sensitivity to distributional information of sound–spelling mappings was already detected by third grade, indicating early acquisition even in children with dyslexia. Although with notable differences, knowledge of the relative frequencies of sound–spelling mapping influenced both reading and spelling. Results are discussed in terms of their theoretical and empirical implications.