THE OBJECTIVES OF THE STUDY WERE--(1) TO DISCOVER VARIATIONS IN LANGUAGE ACHIEVEMENTS OF CHILDREN AT DIFFERENT LEVELS OF MENTAL RETARDATION, (2) TO DISCOVER "OPEN CHANNELS" FOR CURRENT EDUCATION OF THESE CHILDREN, (3) TO CHART THE FREQUENCY OF SPECIFIC DIFFICULTIES IN THE INTAKE AND OUTPUT IDEAS THROUGH LANGUAGE, AND (4) TO IDENTIFY LANGUAGE WEAKNESSES WHICH USUALLY RESPOND RAPIDLY TO REMEDIAL INSTRUCTION. A SERIES OF STANDARD AND CLINICAL TESTS OF LISTENING, READING, SPEAKING, AND WRITING WERE ADMINISTERED TO 209 CHILDREN IN CLASSES FOR THE MENTALLY RETARDED. THESE INCLUDED 67 CHILDREN IN PRIMARY GRADE CLASSES AND 142 CHILDREN IN INTERMEDIATE GRADE CLASSES. LISTENING COMPREHENSION WAS FOUND TO BE THE BEST LANGUAGE CHANNEL FOR LEARNING. AMONG THE PRIMARY GRADE MENTALLY RETARDED, LISTENING COMPREHENSION WAS CONSISTENTLY HIGHER THAN WOULD BE EXPECTED FROM THE MENTAL AGES OF THE CHILDREN. READING ABILITY IS LOWER THAN WOULD BE EXPECTED FOR MENTAL AGE, MARKEDLY BELOW THE LEVEL OF LISTENING COMPREHENSION. INFORMAL TESTS AND OBSERVATIONS SHOWED PRIMARY GRADE CHILDREN TO BE FAIRLY COMPETENT IN SPEAKING AND ORAL RECALL. INTERMEDIATE GRADE CHILDREN DID NOT SHOW THE ADVANCE IN SPEECH COMPETENCE THAT WOULD NORMALLY BE EXPECTED. THE LISTENING COMPREHENSION OF THESE CHILDREN INDICATES A POWER TO HANDLE IDEAS THROUGH LANGUAGE MUCH ABOVE THE EXPECTATIONS FROM MENTAL AGE RESULTS. AN ENRICHED AND SYSTEMATIC PROGRAM IN THE VARIOUS LANGUAGE SKILLS SHOULD PRODUCE MARKED GAINS. (JH)