An exploration of the relation between the language in which a computer program is written and the ease and efficiency of making sure that program is correct. First, definitions are provided for such overadaptive phrases as "validity," "testing," "language," and the like. After a brief survey of features found in current language designs that assist in program checkout, their utility for program validation is assessed. A new view of designing languages is proposed emphasizing the ability to help create correct programs. Some examples illustrating this approach are given and a measure of its utility is suggested: preliminary estimates indicate that more than half of common programming errors could be avoided by suitable language design. The conclusion contains directions for further research to expand and refine this concept. 25 pp. Ref.