Development of phonological and orthographic skill: a 2-year longitudinal study of dyslexic children.

Twenty-one dyslexic children, ages 9-15, were administered a battery of tests on two occasions separated by 2 years to assess the development of word recognition and spelling. The majority of the subjects were receiving intensive small-group instruction and one-on-one tutoring in reading and writing. Correlational and regression analyses supported the assumption that phonological and orthographic processing are distinct but reciprocally related components of word recognition and spelling. However, phonological skill appeared to capture most of the unique variance in word identification for dyslexics and younger normal readers matched on word identification skill. Although the dyslexic children made significant gains over 2 years in overall word identification skill and in aspects of phonological and orthographic processing, they failed to show significant "catch-up" in any component skills relative to age- and reading-level-matched normal readers. In addition, dyslexics made little or no progress on a measure of phonemic analysis, on a decoding task requiring processing at the level of the phoneme, and at spelling words with unusual and irregular orthography. The results are consistent with the hypothesis that dyslexic children have primary deficits in phonological processing of speech and print and secondary deficits in orthographic processing.