The function of strap muscles in speech: pitch lowering or jaw opening

Abstract

This paper reports on one aspect of a continuing study to determine the physiological correlates of the changes in fundamental voice frequency (F0). Several electromyographic (EMG) studies with speech have reported an association of strap‐muscle activity, particularly the sternohyoid, with low F0 and some of these studies suggest that the sternohyoid is actively involved in lowering F0. It has also been suggested, however, that the sternohoid is involved with jaw opening, and that the reported pitch‐lowering effects may actually be the result of jaw opening. To investigate this question an EMG experiment was conducted on one speaker of American English under normal and clenched jaw conditions. The normal utterances were of the form “Bev loves Bob” with emphasis on the various words. The clenched‐jaw data were obtained while the subject held his jaw fixed by biting on a tongue depressor and intoned the corresponding intonation patterns with a fixed vowel carrier /a/. The results indicate that the strap mus...