In this study we investigate the intonational characteristics of the four utterance types statement, wh-question, yes/no-question and declarative question. Readings of two German scripted dialogues were examined to ascertain characteristic features of the F0 contour for each utterance type. Final boundary tone, nuclear pitch accent, F0 offset, F0 onset, F0 range, and the slopes of a topline and a bottomline were determined for each utterance and compared for the four utterance types. Results show that for an average speaker, the final boundary tone, the F0 range, and the slope of the topline can be used to distinguish between the four utterance types. However, speakers may deviate from this pattern and exploit other intonational means to distinguish certain utterance types or choose not to mark a syntactic difference at all.

In order to determine priorities for the improvement of timing in synthetic speech this study looks at the role of segmental duration prediction and the role of phonological symbolic representation in the perceptual quality of a text-to-speech system. In perception experiments using German speech synthesis, two standard duration models (Klatt rules and CART) were tested. The input to these models consisted of a symbolic representation which was either derived from a database or a text-to-speech system. Results of the perception experiments show that different duration models can only be distinguished when the symbolic representation is appropriate. Considering the relative importance of the symbolic representation, post-lexical segmental rules were investigated with the outcome that listeners differ in their preferences regarding the degree of segmental reduction. As a conclusion, before fine-tuning the duration prediction, it is important to derive an appropriate phonological symbolic representation in order to improve timing in synthetic speech.

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