Consonants and vowels in orthographic representations.

It has been argued that orthographic representations-the abstract mental representations of the spellings of words-include orthography-specific information regarding the consonant/vowel (CV) identity of the individual letters that make up a word's spelling. This hypothesis has been used to explain the finding that the substitution errors in the spelling of certain dysgraphic individuals exhibit a striking tendency to preserve the CV identity of the target letters. In this paper, we evaluate the adequacy of two alternative hypotheses that do not posit orthography-specific CV representations. One hypothesis proposes that constraints on the nature of letter substitution come from the phonological representation of a word, and a second hypothesis contends that CV-preserving substitutions are driven by orthotactic knowledge-knowledge of the well-formed letter sequences in the orthography of a language. We present novel tests of these hypotheses using data from four case studies of dysgraphic individuals. The results clearly adjudicate in favour of the claim that orthographic representations contain orthography-specific CV information. In this way, the results support the more general claim that abstract categories are represented within the language system.