Generating pitch accents in a concept-to-speech system using a knowledge base

This paper describes a concept-to-speech system for generating spoken descriptions of routes between places within Macquarie University Computing Department. The Natural Language Generation (NLG) component of the system generates a textual route description marked with intonational information. The discourse structure of the route description is related closely to the knowledge representation of the route. The NLG component includes a pitch accenting algorithm which places appropriate pitch accents on elements of the utterance requiring particular emphasis or stress. Our pitch accenting algorithm uses a domain knowledge base and a discourse history. From these it determines whether information selected to form the content of the utterance is shared mutual domain knowledge, given information, or new information. It can then assign an appropriate pitch accent to one word in each prosodic phrase. The text-to-speech component then determines the appropriate syllable to be accented in the word.