Plausibility , Parsimony , and Theories of Speech *

According to a somewhat unconventional view, speech is managed by a specialization for language-a phonetic module-at the level of action and perception. There, the processes and primitives are specifically phonetic, not, as is more commonly assumed, generally motor and auditory. The less conventional view is nevertheless the more plausible because it (1) better illuminates the biological nature ofthe difference between spoken and written forms of language, and (2) provides the better account of how speech meets the specific requirement of phonological communication that the elements be commutable, as well as the general requirement of all communication systems that there be parity between sender and receiver. Also relevant to the argument of plausibility is the fact that, while the phonetic module is unique to language, it is not without biological precedent, since it has important properties in common with such older (and better understood) specializations as stereopsis and sound localization.