The importance of the accumulating fund of language-related information available to teachers is the result of several developments: (1) There has been an increase in the amount of available research data; (2) The computer has made possible research previously impossible to design; (3) Data are more readily available through centers with acronymic names; (4) Input from the field of linguistics has appreciably widened the scope of research of significance to the teacher; (5) Interrelationships among the language arts and language development have begun to be recognized as matters of importance; (6) Experiments in prelinguistics, biology, phonology, biochemistry and psychology have continued to suggest that the acquisition of language is much more subtle and complex than previously suspected; (7) The impact of mass media is creating "language development mutations" and, as one result, research in the communications field has begun to become of greater relevance to the language arts teacher. Although emphasis throughout this document is placed on books and articles describing or reporting research, general sources in the literature which are based on research are also included. This work is a review of the literature as a whole rather than a digest of research per se. (CK)