Cross-Linguistic Invariants and Variation in Language Development

The goal of this chapter is to present some of the interesting and important aspects of cross-linguistic comparisons which can be made between the acquisition of Japanese and of English. We d o not attempt an exhaustive review of the literature (see, for example, Clancy, in press; Iwata, 1979; Murata , 1968, 1972; Sato, 1978 for reviews of the Japanese literature). We focus instead first on the basic theoretical issues underlying the study of language development in general. Then we selectively describe research that seeks invariants as well as interesting variations in the cross-linguistic circumstances of language development in Japanese and in English. Among the areas of child psychology, language development is perhaps one of the least understood by those outside the specialty. Developmental psycholinguists frequently find themselves forced to explain the major issues in the field, even to their colleagues in developmental psychology. This confusion exists in part because the questions asked by linguists (for an immediate example, see Kuno, this volume) ordinarily have considerable influence on the questions asked by developmental psycholinguists. In an interdisciplinary volume such as this, then, it behooves us to consider these issues. Therefore, we should ask why developmental psycholinguists study child language in general and cross-linguistic child language acquisition in particular. Such a discussion is a prerequisite for any consideration of specific research findings from comparative studies of the acquisition of Japanese and of English, the topic That comprises the second part of this chapter.