A Review of Current Theories Concerning Phonetic Invariance: With Some Implications from Clear Speech

Abstract

One of the classic issues of phonetics is the invariance problem: the lack of one-to-one relationship between a linguistic unit and its corresponding physical properties. Various current theories in speech production and perception concerning the invariance issue are reviewed. Those theories can be categorized into two categories: The first group shares the assumption that phonetic invariance is a reality. The other group approaches the issue by trying to account for the variability. Each theory is reevaluated under the lights of newly formed data from the area of "clear speech" research. And it is argued that the latter position should be taken for speech research and a way of conducting phonetic research in a systematic fashion is proposed.