Articulatory inversion and synthesis: Towards articulatory-based modification of speech

Certain speech modifications, such as changes in foreign/regional accents or articulatory styles, are performed more effectively in the articulatory domain than in the acoustic domain. Though measuring articulators is cumbersome, articulatory parameters may be estimated from acoustics through inversion. In this paper, we study the impact on synthesis quality when articulators predicted from acoustics are used in articulatory synthesis. For this purpose, we trained a GMM articulatory synthesizer and drove it with articulators predicted with an RBF-based inversion model. Using inverted instead of measured articulators degraded synthesis quality, as measured through Mel cepstral distortion and subjective tests. However, retraining the synthesizer with predicted articulators not only reversed the effect of errors introduced during inversion but also improved synthesis quality relative to using measured articulators. These results suggest that inverted articulators do not compromise synthesis quality, and open up the possibility of performing speech modification in the articulatory domain through inversion.