Master's Degree Thesis, August 2000

According to the phonological deficit hypothesis, spelling errors made by dyslexic children are due to sound misperceptions. According to the developmental delay hypothesis, spelling errors are similar to those made by younger, normal progressing children. A study was conducted of vowel spelling data from 53 children who fit the profile of dyslexia at the Middle Tennessee State University Dyslexia Center. Comparison data were taken from a study of first graders conducted by Treiman (1993). The phonological deficit hypothesis predicts that dyslexics should show a high proportion of phonological errors, such as vowel substitutions (BAKE = bek) and omissions (BAKE = bk). The developmental delay hypothesis predicts that dyslexic children's errors should mostly consist of phonologically legal alternatives (BAKE = baik) and letter name spellings (BAKE = bak). Spelling errors from children with dyslexia suggested that they do not make significant numbers of phonologically illegal substitution errors, but instead commit more phonologically plausible errors, similar to first-grade children's spelling patterns. The results of this study seem to be more consistent with the developmental delay hypothesis and may have implications for instructing children diagnosed with dyslexia in spelling.