Articulatory evidence for acoustic goals for consonants

Abstract

Evidence has been found for trading relations between tongue-body raising and upper lip protrusion (measured with an EMMA system) for the vowel /u/, reflecting a ‘‘motor equivalence’’ strategy that should help to constrain acoustic variation [Perkell etal., J. Acoust. Soc. Am. 93, 2948–2961 (1993)]. Theoretically, analogous relations in the transformation between the area function and the acoustic transfer function are possible for the consonants /r/ and /∫/, which are also produced with two independently controllable constrictions, formed by the tongue and by the lips. Such relations might occur more among tokens that are least prototypical, i.e., closest to perceptual boundaries. In a preliminary test of these hypotheses, a single speaker has produced the sounds /r/, /∫/, and /u/, embedded in contexts that might induce differences in prototypicality. Motor equivalence was observed for the /u/ in /tut/ (least prototypical, with the highest F2 values) but not in /pub/ or /hud/. For /r/ and /∫/, anterior displacement of the tongue constriction was positively correlated with upper lip protrusion, providing initial support for the hypothesis that movement goals for the consonants also include acoustic components, which are manifested in a tendency to maintain sufficient front cavity length to help assure acoustic-phonetic distinctiveness. [Work supported by NIDCD.]