Enlisting the aid and cooperation of volunteer schools, Agard and Dunkel (1948) undertook a major investigation of the outcomes of the "aural-oral" methods of teaching foreign languages. The report of this study was published in 1948. From the beginning of their report, the authors admitted the lack of sufficient controls to conduct a proper experiment. However, the results of this survey did not substantiate the earlier claims of the protagonists of the "aural-oral" approach, and the authors listed a need for greater modesty of claims. Specifically, the study did not support the theory that oral training improves reading ability. Furthermore, students receiving "aural-oral" instruction did not demonstrate a superior ability in listening comprehension. The authors concluded by calling for additional research in more carefully controlled situations.
Hamilton and Haden (1950) reported on a three-year study at the University of Texas. In this investigation, three problems of teaching second languages were examined: (1) Do achievement results reflect oral or reading skills in proportion to the extent that the skill was emphasized in the classroom? (2) Is it necessary that grammar be taught? (3) What methods are best for teaching pronunciation? Their major finding was that instruction in the specifics of grammar seemed to have very little effect upon the students' knowledge of morphology and syntax. No definite conclusions were drawn with respect to teaching pronunciation, but it was inferred that (1) descriptions of speech production were helpful; (2) phonetic symbols were beneficial in French, but not in Spanish; and (3) imitation alone was not sufficient to develop a proper pronunciation. The authors also concluded that differing emphases in presentation of material may not necessarily produce corresponding differences in achievement results.