Automatic Duration Weighting in Thai Unit-selection Speech Synthesis

This paper presents the naturalness improvement in Thai unit-selection text-to-speech synthesis (TTS) by automatic weighting of targeted cost. An intuition of the proposed method is that the sensitivity of human perception might be varied to different phonemic and prosodic units. In this work, the unit-selection targeted-cost of each phoneme unit is weighted differently according to its duration statistic and voicing characteristic. Two automatic weighting algorithms, based on the statistical mean and standard deviation of phoneme duration, are comparatively evaluated. A subjective test shows a 0.46 mean-opinion-score improvement over the baseline speech synthesized without targeted-cost weighting.