A perspective on the neurobiology of language. 
This paper provides a perspective on current issues and challenges in the investigation of the neurobiology of language.  It is proposed that the speech/language deficits of aphasic patients reflect impairments in the processing components involved in accessing language.  More specifically, it is hypothesized that many of these deficits result from changes in the activation level of word candidates in the lexicon.  Because word recognition and lexical access processes are crucially involved in virtually all aspects of language processing, such an impairment has repercussions throughout the components of the linguistic grammar.  It is suggested that the intersection of such language behaviors with the identification of underlying neural systems will define future research directions.  Methodological and technological issues are discussed as they impact on current and future research.