The processing of inflected and derived words in writing.

We report on an English-speaking, aphasic individual (RB) with a spelling deficit more severely affecting orthographically irregular words for which phonologically plausible errors (PPEs) were produced. PPEs were observed for all word forms, with the exception of inflectional suffixes, despite the irregular sound-print mappings of many inflectional suffixes (e.g., walked → /wɔkt/). RB's pattern replicates that reported in Badecker, Rapp, and Caramazza (Badecker, W., Rapp, B., & Caramazza, A. (1996). Lexical Morphology and the Two Orthographic Routes. Cognitive Neuropsychology, 13, 161-176). We extended their investigation by examining RB's spelling of derived words and found a selective deficit for derived words compared to inflected words in writing. This selective deficit did not appear to reflect differences in morphological transparency or suffix frequencies that exist between inflection and derivation. This is the first evidence that distinct neural mechanisms support inflection and derivation in spelling.