Synchronization of Speech Rate to User's Personal Tempo in Dialogue Systems and Its Effects

Every individual lives in daily lives in own unique tempo, called Personal Tempo. Tempo is also highly important in dialogue situations, and it is thought that if the tempo can be matched with the conversational partner, it will lead to smoother communication with a higher level of comprehension. Spoken-dialogue systems have been used in many situations, and by personalizing dialogue on the basis of the user's tempo, it is thought that dialogue will be able to make it easier to speak and make people want to speak. Previous research has focused on methods for encouraging users to change their tempo to be in tune with the tempo of their dialogue partner. However, a conversation that differs from the user's tempo can be stressful and burdensome for the user in the process of tuning in. Therefore, we define personal tempo as speech speed, which is the number of moras divided by the duration of speech and propose a speech-speed control method for spoken-dialogue systems. We implemented our method in a spoken-dialogue system that synchronizes speech with the user. We verified the effectiveness of the proposed method by analyzing its impact on the comprehension of speech and user impressions of the spoken-dialogue system. The results indicate that significant differences were obtained with the proposed method between impression and comprehension of the speech content.