DISLEX was originally developed as the lexicon component for the DISCERN system. It was later extended into a more complete model of the mental lexicon, including semantic, orthographic, and phonological lexical modalities. The organization of each modality and the mappings between them are learned based on co-occurrences of symbols and their meanings. DISLEX shows how dyslexic and category-specific aphasic impairments can arise based on the physical organization of the lexical system.