Task-based language learning research has been dominated by an invariable format confined to investigating effect patterns of tasks on language performance irrespective of the role of individual differences in this effect equation. The book revisits this research oversight through an empirical examination of the joint effect of task conditions and goal orientations not only on language learners' oral performance and but also on their speaking development. Building on a processing-based framework, analysis of results elicited by experimental narrative tasks revealed a considerable scope of...