This paper examined the processes that resulted in an adult failing to comprehend the intentions of a boy with high-functioning autism. In a dyadic conversation between an adult and a young boy, the adult used questions to elicit clarification of intentions. The boy's responses were examined frame-by-frame using videotape microanalysis. Two causes of adult misunderstanding were formulaic use of words that confused the listener and directional gaze away from the listener. Questions that used interrogatives often failed to clarify the intention of the boy and yes/no questions appeared suitable to clarify his intention. However, success or failure to clarify an intention was not based solely on differences in the question format. Differences in question content may also have been relevant. Yes/no questions were mainly used to ask about specific actions. On the other hand, interrogative questions were used to handle cognitive or meta-cognitive matters.