Internal structure of phonetic categories: Evidence for within-category trading relations

Phonetically relevant acoustic properties perceptually trade against each other at phonetic category boundaries. The present investigation used a category goodness-judgment task to examine whether such properties also trade against each other in specifying the best exemplars of phonetic categories. The experiments focused on the say-stay distinction, specified by F1 onset frequency and silence duration preceding F1 onset. The main experiment demonstrated a within-category trading relation, such that as F1 onset frequency increased from 230 to 430 Hz a longer silence was required for stimuli to be judged the best exemplars of stay. Two follow-up experiments explored the robustness of this effect. Taken together, the findings underscore the importance of multiple acoustic properties in specifying the internal structure of phonetic categories. (C) 1996 Acoustical Society of America.