In the earliest studies of child language, attention was given to language production as utterances of sound. Association of language with meaning followed as language development and the relationship between language and thought gained serious recognition in the study of child development. The traditional societal view of "a child should be seen and not heard" is singular in loss of historical luster as a pervading truth or value. The pace of study of child language, limited by design and control, gained rapidly in sphere of inquiry as process and product of language development challenged researchers to innovative implementation. Investigators, dates, and nature of inquiry and finding, present an overview of the historical emergence of language development as a major factor in behavior, communication, thought, and learning. This historical review of the literature on the relationship between environment and language development is intended to identify expanding inquiry from points of inception, as concomitant to dramatic political and societal change. The review cites trends and impacting events which shape the emergence of continuing inquiry. (Contains a 105-item bibliography of research published between 1932 and 1969.) (NKA)