This comprehensive monograph 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 import6ance of subcortical circuitry and inner speech and reviews the unfolding or regression of language of language in focal brain lesions, autism, Williams syndrome and developmental disorders of oral and written language.