Changes of Articulatory Movement Accompanying Speech Rate Control in Normal Subjects

—Tongue-Palate Contact Analysis using Electropalatography—

Abstract

In order to clarify changes of articulatory movement accompanying speech rate control, dynamic tongue-palate contact patterns were analyzed by electropalatography. The subjects were nine healthy adults who had no history of speech or hearing disorders. The first sentence from the "Kitakaze passage" was used as the speech sample, and the word-initial alveolar stop /t/ was analyzed. Eight rate control conditions were set, including five oral instructions and three forced rate control methods.
Compared with normal speed, speech rate was significantly lowered by instructions of "Speak slowly" and "Open your mouth wide," and by use of the "mora-by-mora method with finger-counting gestures" and "mora-by-mora and phrase-by-phrase counting with pacing board." In these cases, tongue-palate contact duration was extended and the contact area was expanded. With "phrase-by-phrase counting with pacing board," a slight duration of no tongue contact was observed between the preceding sound and the target /t/. There seemed to be extra time for articulatory movement.
By use of electropalatography, it was objectively confirmed that articulatory movement changed with lowering of speech rate.