Two routes or one in reading aloud? A connectionist dual-process model

A connectionist study of word reading is described that emphasizes the computational demands of the spelling-sound mapping in determining the properties of the reading system. It is shown that the phonological assembly process can be implemented by a two-layer network, which easily extracts the regularities in the spelling-sound mapping for English from training data containing many exception words. It is argued that productive knowledge about spelling-sound relationships is more easily acquired and used if it is separated from case-specific knowledge of the pronunciation of known words. It is then shown how the interaction of assembled and retrieved phonologies can account for the combined effects of frequency and regularity-consistency and for the reading performance of dyslexic patients. It is concluded that the organization of the reading system reflects the demands of the task and that the pronunciations of nonwords and exception words are computed by different processes.