Analysis and HMM-based synthesis of hypo and hyperarticulated speech

Hypo and hyperarticulation refer to the production of speech with respectively a reduction and an increase of the articulatory efforts compared to the neutral style. Produced consciously or not, these variations of articulatory efforts depend upon the surrounding environment, the communication context and the motivation of the speaker with regard to the listener. The goal of this work is to integrate hypo and hyperarticulation into speech synthesizers, such that they are more realistic by automatically adapting their way of speaking to the contextual situation, like humans do. Based on our preliminary work, this paper provides a thorough and detailed study on the analysis and synthesis of hypo and hyperarticulated speech. It is divided into three parts. In the first one, we focus on both acoustic and phonetic modifications due to articulatory effort changes. The second part aims at developing a HMM-based speech synthesizer allowing a continuous control of the degree of articulation. This requires to first tackle the issue of speaking style adaptation to derive hypo and hyperarticulated speech from the neutral synthesizer. Once this is done, an interpolation and extrapolation of the resulting models enables to finely tune the voice so that it is generated with the desired articulatory efforts. Finally the third and last part focuses on a perceptual study of speech with a variable articulation degree, where it is analyzed how intelligibility and various other voice dimensions are affected.