Tongue movement mechanism in different speaking rates

Abstract

In this paper tongue activity during Japanese speech production was examined. Of interest was the identification of potential neural control strategies and biomechanical contributions underlying speech production by evaluating, separately and in combination, kinematic and electromyographic (EMG) activity of the tongue at normal and fast speaking rates. Three normal adult Japanese speakers (three male) served as subjects for this investigation. Hooked-wire electrodes were placed in three tongue muscles; two extrinsic (genioglossus anterior [GGA] and genioglossus posterior [GGP]) and one intrinsic, and two facial muscles (orbicularis oris inferior [OOI] and depressor labii inferior [DLI]). The two-dimensional movement data were recorded electromagnetically on the midsagittal plane using an EMMA system [Perkell etal. (1992)]. Upper lip, lower lip, tongue tip, and tongue body movement were recorded simultaneously with the EMG data. Though a variety of speech tasks were recorded, the present report will focus on three syllable words, /poteto/, in a carrier sentence, /ii−desu/ at a normal speaking rate and a subject-determined fast rate. It was found that EMG and movement characteristics were maintained for both normal and fast rate. Although at a fast speaking rate, movement amplitude were reduced, EMG amplitude were either maintained or somewhat increased.