Dissociation of spelling errors in written and oral spelling: The role of allographic conversion in writing

We describe the spelling performance of a patient who produces phonologically plausible errors (e.g., chare for chair) in oral and written spelling tasks and additionally produces “spelling” errors (e.g., chait for chair) in written but not in oral spelling tasks. The pattern of error performance is used to motivate hypotheses about the structure of the graphemic output lexicon, the phoneme-grapheme conversion system, and the role of the allographic conversion system in writing.