Acoustic features of Japanese words spoken by Japanese natives and non-natives

To investigate acoustic feature differences between Japanese nativeand non-native speakers in spoken Japanese, 29 Japanese words were digitally recorded by 10 each of Japanese, French, Korean, Thai, Taiwanese, and Vietnamese speakers. The results revealed that acoustic features in each language have different tendencies in relative duration, intensity, and fundamental frequency. For example, compared to Japanese natives, Thai and Vietnamese speakers had the tendency of longer relative duration for first and last vowels than Japanese speakers, French speakers had lower relative intensity for all vowels, and all non-native speakers had higher relative fundamental frequency for first vowels but lower relative fundamental frequency for last vowels. It is suggested that the characteristics of each language of non-native speakers cause respective effects on the production of Japanese speech.