A new duration modeling approach for Mandarin speech

A new duration modeling approach for Mandarin speech is proposed. It explicitly takes several major affecting factors, such as multiplicative companding factors (CFs), and estimates all model parameters by an EM algorithm. The three basic Tone 3 patterns (i.e., full tone, half tone and sandhi tone) are also properly considered using three different CFs to separate how they affect syllable duration. Experimental results show that the variance of the syllable duration is greatly reduced from 180.17 to 2.52 frame² (1 frame = 5 ms) by the syllable duration modeling to eliminate effects from those affecting factors. Moreover, the estimated CFs of those affecting factors agree well with our prior linguistic knowledge. Two extensions of the duration modeling method are also performed. One is the use of the same technique to model initial and final durations. The other is to replace the multiplicative model with an additive one. Lastly, a preliminary study of applying the proposed model to predict syllable duration for TTS (text-to-speech) is also performed. Experimental results show that it outperforms the conventional regressive prediction method.