Phonological processes in reading: new evidence from acquired dyslexia

Abstract

This paper investigates the reading performance of two patients with acquired dyslexia. The first patient read aloud all classes of word (85-95 per cent correct), including affixed words, but failed to read aloud non-words. In addition, semantic judgments about written words were shown to be significantly impaired, relative to the ability to read the words aloud. These dissociations support the view that two independent lexical routes are available for reading aloud familiar words, a semantic route and a lexical phonological route. While unable to read aloud non-words, this patient retained the ability to segment orthographic and phonological stimuli. The reading of non-lexical material, therefore, does not appear to be mediated by lexical analogy procedures. Instead, it is suggested that a non-lexical phonological route exists that is clearly independent of lexical phonological procedures. This patient could process isolated written suffixes orthographically, but could only access complete phonological word forms. Suffixed words (but not isolated suffixes) appear to be represented in the phonological word store. The second patient read aloud non-words, but could not give phonetic sounds appropriate to single letters. This dissociation suggests that the reading aloud of non-words is not reliant upon grapheme-phoneme rules.