This volume of The Annual Review of Applied Linguistics explores the connections between psychology and language. In the following chapter, I will show how a field that increasingly informs psychology can also inform the psychological issues that concern applied linguists. Neurobiology and psychology have become more closely integrated in recent years as evidenced by the emergence and development of such disciplinary interfaces as biopsychology and cognitive neuroscience. The recognition that psychological phenomena are subserved by the brain is widely accepted; via developments in neuroimaging technology, the brain is becoming amenable to direct psychological investigation. In this chapter, I examine brain mechanisms that are involved in second language acquisition motivation, in cognitive/motor exploratory activity in learning, and in decision-making aspects of pragmatics in language use.