SOUND LANGUAGE TEACHING RESTS ON THREE THEORETICAL BASES. THE FIRST OF THESE, A HYPOTHESIS OF LANGUAGE ACQUISITION, MAY BE ORIENTED TOWARD THE COGNITIVE APPROACH OR THE PERCEPTIVE APPROACH OR MAY REFLECT THE POINT OF VIEW OF THE BEHAVIORIST. THE SECOND, A MODEL OF GRAMMAR, MAY BE THE PRODUCT OF THE TRADITIONALIST, THE STRUCTURALIST, THE TRANSFORMATIONALIST OR THE TAGMEMICIST. THESE THEORETICIANS IN TURN INFLUENCE THE IMPLEMENTATION OF THE THIRD CONCEPT, A STRATEGY FOR LANGUAGE TEACHING THAT TAKES IN ALL OF THE VARIETIES OF THE "DIRECT METHOD" AS WELL AS THE CONTRASTIVE LINGUISTIC SYSTEM. NO ONE OF THESE THEORIES EXPLAINS ALL GRAMMATICAL STRUCTURES, BUT TRANSFORMATIONAL-GENERATIVE GRAMMAR SEEMS TO HAVE MORE LOGIC AND FEWER LIMITATIONS THAN THE OTHERS. THEREFORE, IT IS PREFERABLE TO FOLLOW AN ECLECTIC PLAN BASED ON A COMPLETE UNDERSTANDING OF ALL SYSTEMS USED. THIS ARTICLE APPEARED IN THE "INTERNATIONAL REVIEW OF APPLIED LINGUISTICS IN LANGUAGE TEACHING," VOLUME 4, NUMBER 4, DECEMBER 1966, PAGES 227-233. (OC)