Language acquisition research involves measuring and describing learners’ knowledge of a language. But a perennial problem is that the evidence stemming from learners’ language production is incomplete; some other method is needed to elicit a more complete data set. Verbal reports have been used extensively in first (L1) and second (L2) language research to provide insight on a variety of issues that production data alone cannot address, such as language learners’ cognitive processing, thought processes, and strategies. Simply put, verbal reports are a learner’s comments recorded either while s/he completes a task or sometime thereafter. Verbal reports completed during a task are referred to as concurrent reports (or think-alouds) and those completed after the task are referred to as retrospective reports.