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Purpose: Researchers evaluating children’s spelling abilities usually score their spellings dichotomously - as correct or incorrect. This type of scoring is not as informative as procedures that take into consideration the plausibility of children’s spellings (Treiman et al., 2016). We examined the spelling abilities of children and adolescents with Williams syndrome (WS), a genetic disorder associated with intellectual disability, to determine if their spellings were based on English orthographic rules. Method: Sixty-six 9–17-year-olds with WS (M=13.50 years, SD=3.14) completed the Wechsler Individual Achievement Test-III (Wechsler, 2009) Spelling subtest. Items 6 to 16 were scored using the Ponto software (Kessler, 2017) to determine the extent to which children’s spelling differed from the correct spelling (the “letter distance"). Letter distance is calculated based on the transformations needed to change the child’s spelling to the correct spelling. Each insertion or deletion is scored 1, and each substitution is scored 1.4. If the word is spelled correctly, its letter distance is 0. Letter distance scores for the child’s spellings were compared to letter distance scores for random spellings, using the Monte Carlo method. Improvement scores were obtained by dividing a child’s sum of letter distances by the sum of random letter distances. Results: Children spelled a median of 10 (MAD=1) of 11 words correctly. Their mean improvement score was 0.89 (SD=0.14), which was significantly better than expected if their spelling had been random, p < .001. Conclusion: Children and adolescents with WS have at least some knowledge of English orthographic spelling rules.

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Spelling, Williams syndrome, intellectual disability, orthographic rules



Use of spelling rules in school-aged children with Williams syndrome

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