This fascinating companion to the award-winning Meaningful Differences in the Everyday Experience of Young American Children reveals how daily child-parent social interactions govern children's language and social development. Based on unparalled data from 2-1/2 years of observing the everyday interactions of 1- and 2-year-old children learning to talk in their own homes, Hart and Risley have charted the month-by-month growth of the children's vocabulary, utterances, and use of grammatical structures. The compelling narrative highlights reliability-tested research findings and is supplemented with numerous transcripts from observations and a list of 2,000 words of children's expressive vocabulary from 19-36 months of age. This book is must-reading for professionals in speech and language, child development, psychology, and education who need to understand how children come to talk as much and as well as their parents and caregivers. Learn more about Hart and Risley's unparalleled study which shows the importance of talking often to young children in their companion book, Meaningful Differences in the Everyday Experience of Young American Children.