This paper discusses recent studies of aphasia from the perspective of theories of normal language structure and processing. Patterns of language breakdown are considered to reflect the componential structure of the language system. In some cases, brain damage is seen to fractionate language along lines suggested by existing psycholinguistic models: certain syndromes can be viewed as more or less isolated disturbances involving lexical, syntactic or phonological components of the language system, or psychological functions such as short-term memory. In other cases, aphasic deficits point to levels of language function not yet well specified by normative models. This review of psycholinguistically oriented research on aphasia supports the effort to construct integrated theories of language functioning on the basis of both normal and pathological performances.