Quality of Experience: Comparison of Synthesized Speech Naturalness Between Apple's Siri and Google Translate Referring to Thai Language

This paper presents application of a speech quality measurement method to evaluate the naturalness of synthesized speech from Text-To-Speech synthesis (TTS) which is an important issue for synthesized speech quality. In this study, the Thai language synthesized speech from Apple's Siri and Google Translate have been evaluated by 48 Thai users. Surprisingly, it has been found that the Mean Opinion Score (MOS) associated with the naturalness of Thai synthesized speech from Apple's Siri and Google Translate are 3.19 and 3.54 respectively. After the analysis, it is confirmed that Google Translate provides better naturalness of Thai synthesized speech than Siri.