Articulatory model for the study of speech production

Study of midsagittal x-ray tracings reveals that the vocal-tract outline can be accurately represented by means of variables specifying the positions of the jaw, tongue body, tongue tip, lips, velum, and hyoid. As the articulators move, they modify the vocal-tract cross-sectional area and the vocal-tract transfer function computed thereform. The speech signal may be synthesized by concatenating the responses to repeated excitation of the quasistatic vocal tract. Vowels are specified in terms of variables denoting the positions of the jaw, tongue body, lips, and velum. Consonants are implemented as transformations on the underlying vowel-derived articulatory states that satisfy given constraints on the position of an articulator relative to the fixed structures. The set of states which satisfy the given constraint corresponds to the allowed productions of the consonant. Coarticulation effects control the selection of the underlying state and thus determine the particular consonant produced. Vowel-consonant-vowel sequences generated with the aid of rules for articulator movement and the articulator-position to vocal-tract cross-sectional-area transformation are intelligible and exhibit coarticulation in agreement with acoustic measurements.