Combined Use of Speaker- and Tone-Normalized Pitch Reset with Pause Duration for Automatic Story Segmentation in Mandarin Broadcast News

This paper investigates the combined use of pause duration and pitch reset for automatic story segmentation in Mandarin broadcast news. Analysis shows that story boundaries cannot be clearly discriminated from utterance boundaries by speaker-normalized pitch reset due to its large variations across different syllable tone pairs. Instead, speaker- and tone-normalized pitch reset can provide a clear separation between utterance and story boundaries. Experiments using decision trees for story boundary detection reinforce that raw and speaker-normalized pitch resets are not effective for Mandarin Chinese story segmentation. Speaker- and tone-normalized pitch reset is a good story boundary indicator. When it is combined with pause duration, a high F-measure of 86.7% is achieved. Analysis of the decision tree uncovered four major heuristics that show how speakers jointly utilize pause duration and pitch reset to separate speech into stories.