The progression from newborn to sophisticated language user in just a few short years is often described as wonderful and miraculous. What are the biological, cognitive, and social underpinnings of this miracle? What major language development milestones occur in infancy? What methodologies do researchers employ in studying this progression? Why do some become adept at multiple languages while others face a lifelong struggle with just one? What accounts for declines in language proficiency, and how might such declines be moderated? Despite an abundance of textbooks, specialized monographs, and a couple of academic handbooks, there has been no encyclopedic reference work in this area--until now. The Encyclopedia of Language Development covers the breadth of theory and research on language development from birth through adulthood, as well as their practical application. Features: This affordable A-to-Z reference includes 200 articles that address such topic areas as theories and research tradition; biological perspectives; cognitive perspectives; family, peer, and social influences; bilingualism; special populations and disorders; and more. All articles (signed and authored by key figures in the field) conclude with cross reference links and suggestions for further reading. Appendices include a Resource Guide with annotated lists of classic books and articles, journals, associations, and web sites; a Glossary of specialized terms; and a Chronology offering an overview and history of the field. A thematic Reader's Guide groups related articles by broad topic areas as one handy search feature on the e-Reference platform, which includes a comprehensive index of search terms. Available in both print and electronic formats, Encyclopedia of Language Development is a must-have reference for researchers and is ideal for library reference or circulating collections. Key Themes: Categories Effects of language on cognitive development Fundamentals, theories and models of language development Impairments of language development Language development in special populations Literacy and language development Mechanisms of language development Methods in language development research Prelinguistic communicative development Social effects in language acquisition Specific aspects of language development