The convergence of several lines of psycholinguistic and sociolinguistic research suggests possible explanations for age-related influences on language acquisition. These factors, which include cognitive development, sociocultural context, affective factors, and language input, can be helpful to language educators. By being alert to the cognitive variables active in children entering the classroom, educators can base instruction on what the individual learners are ready to accomplish. The experiences that a child has with language at home and in the community may influence later success in school and may be age-related. Mastery of different kinds of language use, or elaborated code, facilitates both language acquisition and academic achievement in general. Affective factors such as motivation, anxiety, self-confidence, and other individual characteristics are seen by some as partially responsible for the differences between adult and child language acquisition. Finally, the nature of language samples presented to the learner as input for the acquisition process is a significant, age-related factor, since older learners receive less simplified input than do children and must develop skills in gaining needed linguistic information. Teachers following research in these areas are more likely to devise language teaching systems sensitive to the needs and potential of individual learners. (MSE)