A short latency unit selection method with redundant search for concatenative speech synthesis

A new method for short-latency unit selection is proposed. For prompt response in concatenative speech synthesis systems with large unit databases, waveforms should be output before all speech segment units of an utterance are determined. For that purpose, short-latency unit selection algorithms were introduced in our previous study. However, the short-latency unit selection may cause degradation of quality because units that consist of the optimal unit sequence may be pruned by forcible unit determination on the search. In the proposed method, the degradation of quality is suppressed by redundantly expanded hypotheses based on N-best search. The results of unit selection experiments in a practical configuration indicate that the proposed method is superior to the conventional DP search method when latency in unit selection is set to be short.