Modeling of Fundamental Frequency Contours for Thai Dialects with Large Speech Database

Abstract

In four core regions of Thailand, there are four main dialects including central, north, northeast and south dialects. The prosody is significantly unique for each dialect. One important factor determining the prosody is the fundamental frequency. As a result, modeling of Fundamental frequency (F0) contour is very important for the natural speech processing. Even though there are many modeling techniques for modeling the F0 contour. In this study, the Fujisaki’s model has been selected because of its achievement in modeling of various Thai speech units. This study proposes an analysis of model parameters of Thai speech prosody for four regional dialects and two genders. Seven derived parameters from the Fujisaki’s model are as follows. The first parameter is baseline frequency which is the lowest level of F0 contour. The second and third parameters are the numbers of phrase commands and tone commands which reflect the frequencies of surges of the utterance in global and local levels, respectively. The fourth and fifth parameters are phrase command and tone command durations which reflect the speed of speaking and the length of a syllable, respectively. The sixth and seventh parameters are amplitudes of phrase command and tone command which reflect the energy of the global speech and the energy of local syllable. In the experimental results, the large speech material of each regional dialect includes 50 samples of 50 sentences with male and female speech. It can be obviously seen that most of the proposed parameters can distinguish four kinds of regional dialects explicitly. The results reveal that the proposed parameters of Fujisaki’s model can distinguish the regional dialects explicitly.