Implementing and evaluating an integrated approach to modeling German prosody

The perceived quality of synthetic speech strongly depends on its prosodic naturalness. Departing from works by Mixdorff on a linguistically motivated model of German intonation based on the Fujisaki model, the current paper presents statistical results concerning the relationship between linguistic and phonetic information underlying an utterance and its prosodic features. These results were employed for training an FFNN-based integrated prosodic model predicting syllable duration and energy along with syllable-aligned Fujisaki control parameters. A novel method of perceptual evaluation was applied, comparing resynthesis stimuli created by controlled prosodic degrading of natural speech with stimuli created using the integrated model. The results indicate that the integrated model generally receives better ratings than degraded stimuli with comparable durational and F0 deviations from the original. An important outcome is the observation that the accuracy of the predicted syllable durations is a by far stronger factor with respect to the perceived quality than the accuracy of the predicted F0 contour.