In light of the growing interest in the cognitive approach to task in second language (L2) research, comparatively little has been done to examine such effect over time and the role of individual differences (IDs). The present study was designed to verify some longitudinal evidence for the role of tasks in L2 production and whether IDs, in the example of goal orientations, may have a bearing on that role. Thirty lower-intermediate level undergraduates performed narrative tasks during a five-month period and some were subsequently interviewed. Analysis of the data suggests that goal orientation and task conditions have a combined effect on speaking performance and development. In view of that, this paper questions the validity of findings disregarding learner variability and argues for the necessity to direct future research focus at how IDs may interact with tasks in different ways to influence L2 production.