Evaluating Prosodic Processing for Incremental Speech Synthesis

Incremental speech synthesis (iSS) accepts input and produces output in consecutive chunks that only together result in a full utterance. Systems that use iSS thus have the ability to adapt their utterances while they are ongoing. However, starting to process with less than the full utterance available prohibits global optimization, leading to potentially suboptimal solutions. In this paper, we present a method for incrementalizing the symbolic pre-processing component of speech synthesis and assess the influence of varying "lookahead", i. e. knowledge about the rest of the utterance, on prosodic quality. We found that high quality incremental output can be achieved even with a lookahead of less than one phrase, allowing for timely system reaction.