Listeners comprehension of phrase final rising pitch on declarative utterances, or uptalk, was examined to test the hypothesis that prolongations might differentiate conflicting functions of rising pitch. In Experiment 1 we found that listeners rated prolongations as indicating more speaker uncertainty, but that rising pitch was unrelated to ratings. In Experiment 2 we found that prolongations interacted with rising pitch when listeners monitored for words in the subsequent utterance. Words preceded by prolonged uptalk were monitored faster than words preceded by non-prolonged uptalk. In Experiment 3 we found that the interaction between rising pitch and prolongations depended on listeners beliefs about speakers mental states. These results demonstrate that form/function mappings may need to take temporal information into account. They also demonstrate that form/function mappings are not predetermined, but can vary depending on listener expectations.