A study on the effect of speech rate on perception of spoken easy Japanese using speech synthesis

“Easy Japanese” is a controlled natural language, which is designed to convey information correctly in Japanese language to people of various nationalities. In this research, we used synthesized speech with various speech rates to investigate how the speech rate correlates with the perception of Easy Japanese for non-native speakers of Japanese. As a result, we found that the speech rates of 320 and 360 mora per minute are perceived to be close to the ideal speech rate.