ABSTRACT
Scientists investigating the processes underlying human speech and language behavior face a difficult problem. The superficial manifestations of oral communication can be observed rather directly. However, the underlying neural processes, seemingly critical to optimal understanding, are almost wholly opaque. Although it is possible to draw certain inferences concerning these neural processes from speech and language deficits associated with focal brain damage, these inferences are limited inherently by the rapid and sub-
stantial reorganizational processes that occur with loss of nervous system tissue (cf. Asanuma & Arissian, 1984; Glassman, 1978; Laurence & Stein, 1978). To overcome these difficulties, multiple and often complementary approaches have evolved. Commonly, these approaches include:
1. Identification of various hypothetical constructs or abstractions from linguistic or information processing models,
2. Classification of oral communication patterns in relation to those constructs, and
The constructs or abstractions commonly employed include planning, programming, serial and parallel processing, parsing, syntax, phonology, modularity, etc. Implicit in the use of such hypothetical constructs or abstractions is the assumption that they reflect essential aspects of underlying nervous system organization and function. Indeed, one major difference among the various theoretical and methodological approaches to understanding speech and language behavior appears to be the degree to which hypotheses and dependent measures explicitly reflect extant knowledge of the nervous system. From our perspective, explicit consideration of nervous system anatomy and physiology is critical if we are to make long-term progress in this area. Without this constraint, it is all too easy to conjure up a large number of equally plausible, abstract hypotheses to explain a given set of communication behaviors or deficits thereof. Despite the intellectual exercise that is provided by such effects, one must recognize that little may be gained in understanding the critical nervous system functions for speech and language.
