The Articulatory Synthesis program (ASY) is a software speech synthesis system. At the heart of this system is a model of the vocal tract in the midsaggital plane (viewed from the side, as shown above). There are 6 key parameters in this model: the tongue body center (C, 2 degrees of freedom (df)), the tongue tip (T, 2 df), the jaw (J, 1 df), the lips (L, 2 df), the velum (V, 1 df), and the “hyoid” (H, 2 df, controlling larynx height and pharynx width). The tongue tip is a structure that rests on the tongue body, which is implemented as a ball. In turn, the tongue ball rests on the jaw. In the actual program, the vocal tract can be reconfigured by clicking on one of the articulators, and repositioning it.

To explore the underlying geometries of the key articulators, click on their names in the list, above.