J. S. Perkell M. L. Matthies M. A. Svirsky M. I. Jordan
Speech Commun. Group, Res. Lab. of Electron., MIT, Cambridge, MA 02139
In a preliminary study [Perkell et al., J. Acoust. Soc. Am. 93, 2948 (1993)] subjects demonstrated a trading relation (negative correlations) between tongue-body raising and lip protrusion in production of the vowel /u/. Data analyses indicated an increased tendency for the trading relation to occur at high values of F2. The tentative hypothesis is that when more than one articulator contributes to producing a particular acoustic cue and a source of variation displaces one of the articulators away from its target, compensating (complementary) adjustments are made in the programmed displacements of the other contributing articulator(s) to help constrain the acoustic variation. These adjustments should be more strongly expressed in tokens that are close to phonemic boundaries, where variation in the displacement of one of the contributing articulators could result in production of the wrong sound. This work has been extended with two new subjects. halfway through the experiment a bite block was placed in the subject's mouth to introduce an additional source of variation. One subject strictly used coordination (i.e., positive correlation) to produce /u/ and did not alter this strategy with the bite block. Negative correlations were found for the other subject in subsets with relatively high values of F2. [Work supported by NIDCD.]