Paragraph-based Prosodic Cues for Speech Synthesis Applications

Speech synthesis has improved in both expressiveness and voice quality in recent years. However, obtaining full expressiveness when dealing with large multi-sentential synthesized discourse is still a challenge, since speech synthesizers do not take into account the prosodic differences that have been observed in discourse units such as paragraphs. The current study validates and extends previous work by analyzing the prosody of paragraph units in a large and diverse corpus of TED Talks using automatically extracted F0, intensity and timing features. In addition, a series of classification experiments was performed in order to identify which features are consistently used to distinguish paragraph breaks. The results show significant differences in prosody related to paragraph position. Moreover, the classification experiments show that boundary features such as pause duration and differences in F0 and intensity levels are the most consistent cues in marking paragraph boundaries. This suggests that these features should be taken into account when generating spoken discourse in order to improve naturalness and expressiveness.