It is almost universally believed that learning a language later in life is more difficult than learning one earlier in life. Explanations for this "age-of-acquisition" effect have come in two varieties: those that implicate maturation of the brain, and those that implicate the effects of experience with a first language. Both explanations implicate the same underlying cause for the age-of-acquisition effect, namely, a reduction in neural plasticity resulting from maturation or experience. However, there is suprisingly little direct evidence to support this claim. I will describe a series of studies in which we measured changes in brain activity that accompany the earliest stages of second-language learning. Contrary to what would be expected given conventional beliefs about language learning, we report dramatic changes in brain activity that occur with minimal linguistic input. These changes are not random but instead quickly begin to approximate native-like responses, and become increasingly native-like with increasing exposure to the language.