ONE APPROACH TO CHILD LANGUAGE ACQUISITION IS THAT OF TRANSFORMATIONAL, GENERATIVE GRAMMAR WHICH EMPHASIZES MAN'S ABILITY TO UNDERSTAND AND PRODUCE AN UNLIMITED VARIETY OF SENTENCES THROUGH CONTROL OF A LIMITED NUMBER OF LANGUAGE RULES. THUS, A CHILD LEARNS TO SPEAK BY DEVELOPING HIS OWN THEORIES OF THE STRUCTURE OF HIS LANGUAGE. STUDIES OF RUSSIAN AND ENGLISH CHILD LANGUAGE ACQUISITION SHOW THAT THE PROCESS OF MAKING THESE RULES IS QUITE SIMILAR, IN SPITE OF THE IMPORTANT STRUCTURAL DIFFERENCES BETWEEN THE TWO LANGUAGES. IN BOTH LANGUAGES, FOR EXAMPLE, THE UNMARKED FORMS OF LEXICAL ITEMS ARE LEARNED FIRST, SIMPLE SENTENCES NEXT, AND MORPHOLOGY LAST. BOTH RUSSIAN AND ENGLISH CHILDREN LEARN THIS WAY, IN SPITE OF THE FACT THAT WORD ORDER IS LESS IMPORTANT THAN INFLECTION IN RUSSIAN. IT WOULD SEEM THEN THAT EVERY CHILD'S BUILT-IN "LANGUAGE ACQUISITION DEVICE" FAVORS BEGINNING LANGUAGE WITH ORDERED UNMARKED CLASSES, REGARDLESS OF THE DEGREE OF CORRESPONDENCE OF SUCH A SYSTEM WITH THE INPUT LANGUAGE. SIMILAR PATTERNS OF GENERALIZATION, OVERGENERALIZATION, AND LEARNING OF GRAMMATICAL DISTINCTIONS CAN ALSO BE FOUND IN ENGLISH AND RUSSIAN LANGUAGE ACQUISITION. THESE OBSERVATIONS INDICATE THAT A GREAT DEAL MAY BE LEARNED ABOUT GENERAL CHILD LANGUAGE ACQUISITION THROUGH COMPARING RESULTS OF STUDIES DONE IN DIFFERENT LANGUAGE FAMILIES. THIS PAPER WAS READ AT A SYMPOSIUM ON GRAMMAR AND VERBAL BEHAVIOR IN CHILDREN, CONVENTION OF WESTERN PSYCHOLOGICAL ASSOCIATION (HONOLULU, JUNE 18, 1965). (JD)