Language learning is complex and mysterious--because of the many diverse factors that affect its development and because of the many unanswered questions about its nature. Even so, the efforts of countless researchers have provided sufficient knowledge to prompt some recommendations about how adults may nurture the language and literacy development of children. This paper, written especially for the beginning educator, brings together a body of essential knowledge about language and literacy development with implications for instruction and evaluation. Discussed are universals and differences in language development, and the relationship between language and thought. Research is reviewed on several areas of written language development, including: (1) connecting oral and written language; (2) linguistic awareness; (3) children's early writing development; and (4) interrelationships between oral and written language. Models for teaching language and literacy are also discussed, and the instructional implications of two, the holistic model and the subskills model, are detailed. These two models are also critiqued and compared, and an interactive approach, using aspects from both models, is suggested. The classroom as context for language learning is another topic of review. Implications, drawn from the research review, for instruction and evaluation are listed. (CJ)