Defining Laughter Context for Laughter Synthesis with Spontaneous Speech Corpus

In this paper, conversational laughter was synthesized by a statistical model-based speech synthesis framework using spontaneous speech corpora. The phonetic transcriptions of natural laughter in these corpora were annotated, and the context required to synthesize the laughter that accompanies speech sounds was defined from the perspective of the (1) phonetic properties of the current segment, (2) phonetic properties of previous and succeeding segments, and (3) positional factors of the current segment or laughter bout. Laughter was synthesized using the defined context and the framework of HMM-based speech synthesis. To confirm the influence of the contextual factors on the naturalness of speech, a subjective evaluation was performed. As the result of the evaluation, the naturalness of the entire utterance was improved by using the contextual factors defined in this study. This result confirmed the importance of defining the appropriate context to synthesize natural conversational laughter.