ABSTRACT
One of the fundamental questions that concern the neuropsychologist of language is whether language processing goes through a sequential (horizontal) series of processes common to all cognitive skills (e.g., perception, memory, reasoning), or whether language is represented in the brain as a vertical system independent of other cognitive functions. It will be argued that neuropsychological evidence from Japanese dyslexia and dysgraphia as well as from polyglot aphasia points to the organization of cognitive skills into independent (though interactive) neurofunctional modular systems, not dependent on a number of common basic processes that would underlie all cognitive functions.
