Introduction

Preview

The language signal is generated, and perceived, by the operation of some highly specialised biological systems: auditory and visual pathways from sensory organs to the brain, and motor pathways from the brain to the vocal tract and the hand–arm system. Within the brain itself are ultimately founded not just the representations of the language signal, in its various forms, but also those mediating functions that constitute our general language and cognitive abilities. Before we launch into a consideration of a large and technical research field, we should pause to ask ourselves what we may expect to learn of the nature of language processing from a consideration of what is currently known about these biological systems.

In general, the situation may be likened to one or other of the following: in the best case, monitoring the observable performance of some device such as a television set while systematically inspecting and manipulating its circuitry; in the worst case, speculating on the functions of a building by considering its architectural properties. We cannot expect, in even the best case, that biological investigation will explicate concepts such as ‘hearing speech’, or ‘knowing a language’, any more than we would expect to get closer to the images on a TV screen by looking in the back of the box. Our expectations must rather be in the direction of gathering evidence that will eventually constrain our understanding of the principles of language processing.