The long term aim of the project is to identify those features of the developmental environment of disadvantaged children that result in developmental impairment and mental retardation. Also the plan is to design intervention strategies to improve crucial features of their environment during infancy, the preschool years, and through the school years and beyond. Infants and young children considered to be at risk for developmental disturbances are identified and intervention efforts are made through a pediatrics clinic and home visits, through a language training program and through academic training in the schools and the homes. The pediatric clinic research relates to a variety of health care problems that are identified through pediatric services. The language research relates to early vocabulary development and involves both acquisition and intervention data for the children, and intervention change data for the parents. The academic studies involve classroom organization and teaching procedures in the school and the home to increase the child's opportunities to respond and the amount and quality of interactions occuring during the day. These accounts, in turn, are analyzed in regards to school achievement. These intevention efforts are combined to improve the developmental conditions for disadvantaged children.