How does our early experience with language impact the human brain, higher cognitive functions, and learning? In this presentation, I will focus on research that we have conducted spanning three decades in which we combined behavioral methods with functional neuroimaging (PET and fMRI) to investigate how neural recruitment is influenced by the age of acquisition/exposure (AoE), proficiency in the language, and the distinctive characteristics of languages. I will discuss the use of relatively new anatomical techniques such as voxel-based morphometry-VBM, cortical thickness measures, and diffusion tensor tractography to enhance our understanding of the critical-period phenomena and neural plasticity in the human brain. The program of research addresses the extent to which the human brain has the capacity to change as a result of learning. Here, we specifically investigate the extent to which the neural patterns are fixed and the extent to which the patterns can be altered later in life. The results of these studies reveal the neural underpinnings of human brain development in relation to the age of language exposure, and they suggest periods when learning language are most optimal in early life.
