Phonetic aspects of high level of naturalness in speech synthesis

Abstract

The paper is concerned with the phonetic aspects of speech synthesis of Russian vowels with the use of a voice source signal. An original method of recording the glottal wave synchronously with an output speech signal was employed to obtain the experimental material. Several types of perceptual experiments were carried out. The comparison of the recorded signals allowed us to analyze the structure of the speech signal at different stages of its generation. The source-filter interaction is analyzed by speech signal filtering. The transfer functions of the articulation for the Russian vowels were obtained. The transfer functions and voice source signals of different vowels were used to generate new signals. The resulted signals were analyzed. We examined the way the fundamental frequency, voice quality and a type of phoneme influence the source-filter interaction. In the paper the perceptual experiments, acoustic analysis and signal generation results are presented.