The effect of a formal, structured approach to language development on preschool children is the subject of this project study. From August 1965 to August 1966, 157 programs administered to 1,663 children explored mental ability, auditory and visual discrimination, language use, vocabulary, and motivation. Children attending day care centers, nursery schools, and Head Start classes were tested, and the following observations were noted: (1) childre n from poor homes have inferior ability to discriminate spoken word sounds; (2) when children are given interesting materials, their verbal output shows no differentiation; and (3) motivation is equal in advantaged and disadvantaged children. New tests are needed to measure vocabulary, auditory and visual discriminations. Experimental studies proved three-dimensional toys do not produce superior learning, and repetition of grammatical sentences is preferred to story-telling in developing verbal fluency. As a result of assessments and experiments, the project proposes a 30-week program to develop familiarity and facility with language in science, mathematics, social studies, literature, language usage, and logical processes on a preschool level. The program would occupy only 15 minuets of the school day and would not minimize the productive value of present day care center programs. (DO)