Graduation Year


Document Type




Degree Granting Department

Communication Sciences and Disorders

Major Professor

Sylvia F. Diehl, Ph.D.

Committee Member

Ruth Huntley Bahr, Ph.D.

Committee Member

Elaine R. Silliman, Ph.D.


phonology, orthography, autism, POMAS, literacy


The goal of this study was to examine the spelling errors of children with Autism Spectrum Disorder (ASD) when asked to spell morphologically complex words. Specifically, this study sought to determine if percent accuracy across morphological areas would be similar to patterns noted in typical developing children, correlate with participant age, and correlate to performance on standardized measures of achievement. Additionally, the study wanted to highlight the types of errors made by children with ASD on homonyms and the specific linguistic patterns noted when spelling derivational and inflectional word types.

Participants included 29 children diagnosed with Autism, PDD-NOS, and Asperger’s Disorder, ages 8-15 years. The spelling protocol consisted of 36 words differing in morphological complexity, including homonyms, inflections and derivations. The derivational categories included: no shift, orthographic shift, phonologic shift, and orthographic + phonologic shift words (Carlisle, 2000). Spelling errors were analyzed both quantitatively and qualitatively. The qualitative analysis used a unique coding system, the Phonological, Orthographic, and Morphological Analysis of Spelling (POMAS; Silliman et al., 2006), which identified both the linguistic category of an error, as well as the specific linguistic feature in error.

Results indicated that the spelling errors of children with ASD seemed to follow a developmental pattern that was similar to typically developing children (Carlisle, 1988; 2000). To be specific, phonologic and orthographic+phonologic shift categories evidenced significantly more errors than the no shift, orthographic shift, and inflections categories, which were not significantly different from each other. As expected, academic achievement, as measured by letter-word decoding, spelling, and age, were correlated with morphological spelling ability.

Findings supported the use of the POMAS as a coding measure sensitive to spelling error patterns found in children with ASD. Several common feature errors emerged including: 1) vowel errors, 2) consonant deletions, 3) letter doubling, 4) derivational suffix errors, and 5) whole word substitutions. Overall, this heterogeneous group of spellers fit into three profiles of spelling ability: 1) competent spelling ability, 2) morphologically challenged spellers, and 3) generally challenged spellers. Hence, qualitative investigations of spelling errors play a crucial part in the characterization of spelling skill in children with ASD.