// Annual Review of Applied Linguistics (2005) 25, p. 98–111.
Language learning is a complex set of processes that largely take place in the learner’s head. The extent to which learners consciously focus on specific aspects of language, the degree to which they notice particular features of language, and how this is done has been the object of considerable debate in different theoretical approaches to second language acquisition. For researchers in second language acquisition, one dilemma is how to find out what learners notice, and how, if at all, they incorporate this into their developing linguistic knowledge. Here, I discuss three approaches to researching learner cognitive processes that can be used to identify the knowledge that learners have about their second language, and obtain some insights into the cognitive processes of learners. These approaches have the potential to contribute to our understanding of how learners learn a second language, and, therefore, how this task may be facilitated. The first approach attempts to tap directly into the learner’s thought through the use of think-aloud protocols, whereas the second involves having learners engage with activities that encourage them to talk aloud, thus providing insights into their thought processes. The third approach uses planning effects on task performance to investigate how learners monitor their language.