論文アブストラクト：Voice User Interfaces (VUIs) are growing in popularity. However, even the most current VUIs regularly cause frustration for their users. Very few studies exist on what people do to overcome VUI problems they encounter, or how VUIs can be designed to aid people when these problems occur. In this paper, we analyze empirical data on how users (n=12) interact with our VUI calendar system, DiscoverCal, over three sessions. In particular, we identify the main obstacle categories and types of tactics our participants employ to overcome them. We analyzed the patterns of how different tactics are used in each obstacle category. We found that while NLP Error obstacles occurred the most, other obstacles are more likely to frustrate or confuse the user. We also found patterns that suggest participants were more likely to employ a "guessing" approach rather than rely on visual aids or knowledge recall.