In order to investigate speech accommodation--the way in which communicators influence each other's speaking patterns and rhythms--a study examined its occurrence, as well as the extent of a conversational partner's influence, and the influence of interpersonal uncertainty and differences in arousal level upon that accommodation process. Sixty-five pairs of undergraduate subjects discussed a problem situation, uttering a single given sentence both before and after their conversation. These pre- and post-conversation sentences were measured for speaking rate, utterance length, and vocal jitter, and comparatively analyzed. Results showed that a conversational partner's influence was substantial, and suggest that interpersonal uncertainty and differences in arousal level are both influencing factors in speech accommodation. (Twenty-nine references and five tables of data are attached.) (SR)