Tests three groups of dyslexic children (mean ages 8, 13, 17 years) and three groups of normal achievers (matched for age/IQ) for sound categorization and phoneme deletion, which allows comparison across chronological age and reading age. Finds that children with dyslexia performed significantly worse than their reading age controls on both tasks. Extends previous findings on phonological awareness deficits in dyslexia. (PA)