TOWARD ARTICULATORY-ACOUSTIC MODELS FOR LIQUID APPROXIMANTS BASED ON MRI AND EPG DATA .2. THE RHOTICS

Magnetic resonance images of the vocal tract during sustained producti on of [(sic)] by four native American English talkers are employed for measuring vocal-tract dimensions and for morphological analysis of th e 3D vocal tract and tongue shapes. Electropalatography contact profil es are used for studying inter- and intra-talker variabilities. The vo cal tract during the production of [(sic)] appears to be characterized by three cavities due to the presence of two supraglottal constrictio ns: the primary one in the oral cavity, and a secondary one in the pha ryngeal cavity. All subjects show a large volume anterior to the oral constriction, which results from an inward-drawn tongue body, an anter ior tongue body that is characterized by convex cross sections, and a concave posterior tongue body shape. Inter-subject variabilities are o bserved in the oral-constriction location and the way the constriction is formed. No systematic differences are found between the 3-D vocal tract and tongue shapes of word-initial and syllabic [(sic)]s. Tongue- shaping mechanisms for these sounds and their acoustic implications ar e discussed. (C) 1997 Acoustical Society of America.