This comprehensive monograph is dedicated to the late Dr. Elizabeth Bates of San Diego and Rome who built so many bridges between brain development and function in a variety of languages. It updates progress in understanding children s language learning and its pathologies. It stresses the neurologic basis of normal language acquisition and the consequences of a variety of disorders using such tools as detailed analysis of language comprehension, production, and use, as well as functional brain imaging, and electrophysiology. It also underlines the importance of subcortical circuitry and inner speech, and reviews the unfolding or regression of language in focal brain lesions, autism, Williams syndrome, and developmental disorders of oral and written language.