Suprasegmental acoustic patterns in speech can convey meaningful information and affect listeners' interpretation in various ways, including through systematic analog mapping of message-relevant information onto prosody. We examined whether the effect of analog acoustic variation is governed by the acoustic properties themselves. For example, fast speech may always prime the concept of speed or a faster response. Alternatively, the effect may be modulated by the context-dependent interpretation of those properties; the effect of rate may depend on how listeners construe its meaning in the immediate linguistic or communicative context. In two experiments, participants read short scenarios that implied, or did not imply, urgency. Scenarios were followed by recorded instructions, spoken at varying rates. The results show that speech rate had an effect on listeners' response speed; however, this effect was modulated by discourse context. Speech rate affected response speed following contexts that emphasized speed, but not without such contextual information. (Contains 1 table, 2 figures and 1 note.)