Automatic Prosody Generation in a Text-to-speech System for Hebrew

The paper presents the module for automatic prosody generation within a system for automatic synthesis of high-quality speech based on arbitrary text in Hebrew. The high quality of synthesis is due to the high accuracy of automatic prosody generation, enabling the introduction of elements of natural sentence prosody of Hebrew. Automatic morphological annotation of text is based on the application of an expert algorithm relying on transformational rules. Syntactic-prosodic parsing is also rule based, while the generation of the acoustic representation of prosodic features is based on classification and regression trees. A tree structure generated during the training phase enables accurate prediction of the acoustic representatives of prosody, namely, durations of phonetic segments as well as temporal evolution of fundamental frequency and energy. Such an approach to automatic prosody generation has lead to an improvement in the quality of synthesized speech, as confirmed by listening tests.