A review of recent research in child language development examines how this research can be used to inform policy that will enhance the capabilities of English-speaking and non-English-speaking children to develop strong language skills and promote the success of at-risk children. Focus is on the research most applicable to policy planning. First, a brief overview of American policy on language in education and the issues and attitudes clouding discussion of English-only and bilingual approaches is provided. Two longer sections make up the body of the discussion. One section addresses knowledge of the child's first-language development, and the other section looks at knowledge of child language development in bilingual settings. Educational implications of each are offered. A concluding section identifies other educational policy issues that are profoundly influenced by policy on language. A 38-item selected bibliography is included. (MSE)