To respond to recent calls for examining oral fluency from a broader social and communicative perspective, the current study aimed at investigating the effects of task communicative function on second language (L2) and first language (L1) speakers' fluency. Designing tasks that represent three different communicative functions (congratulations, bad news, and complaint), we collected data from 40 Spanish L2 learners of English, 20 L1 English speakers, and 20 L1 Spanish speakers. The data were analysed for a range of measures of speed, composite, breakdown, and repair fluency. Results of the statistical analyses (descriptive, Multivariance Analysis of Variance (MANOVA), and two-way mixed Analysis of Variance (ANOVAs)) suggested that task communicative function had an impact on the speakers' performance, with bad news eliciting the slowest speech and most mid-clause pauses, and complaint the fastest with fewest end-clause pauses. Significant differences were observed across the tasks for speech rate and end-clause pauses in the L1 English group, but the results were nonsignificant for task effects in the L1 Spanish and L2 English groups. The three language groups' fluency was statistically different, highlighting (a) cross-linguistic differences between L1 Spanish and L1 English speakers and (b) differences between L1 and L2 English speakers.