The speaking style of an interjection contains discriminative features on its expressed intention, attitude or emotion. In the present work, we analyzed acoustic-prosodic features and the paralinguistic functions of two variations of the interjection “un”, a lengthened pattern “uun” and a repeated pattern “unun”, which are often found in Japanese conversational speech. Analysis results indicate that there are differences in the paralinguistic function expressed by “uun” and “unun”, as well as different trends on F0 contour types according to the conveyed paralinguistic information.