Before I start, clarification of the condition under which the comparison is going to be made is absolutely necessary in order that unnecessary controversy due to different understanding of the concepts should not arise. Both child and adult are too broad words and both of which are divided into sub-stages by scholars who study human's cognitive development and language learning. For instance, children before puberty undergo four major intellectual development stages according to Piaget. (Yue: 51) Adults are also observed to differ significantly in cognitive abilities such as memory span and auditory perception (Scott, 1994; Hatch: 223). Therefore I hereby define the children in my discussion as those of elementary school age, i.e. between six and twelve, since children of this age span on the one hand are old enough to sit in classroom and be taught a foreign language, and on the other they share some common features such as rapid cognitive and communicative skills development. (Owens, 1996) Adults, in my discussion, are those who have past their puberty, and at the same time are not too old to deteriorate in memory span or hearing ability. To make them typical, my "adults" are in their twenties or early thirties. .
It would also be helpful to state in the beginning my purpose of making the comparison, as it predisposes the organization of my argument. Though the comparison between adults and children is naturally followed by an interesting question "who is better language learner, adult or child," I am reluctant to make the judgment. Learners could be better either by learning faster in the beginning stages or by ultimately attaining a higher proficiency level. If adults do the former and children the later, which is most possibly the case, then problem arises as to decide who is better. Moreover it is not as meaningful to make the distinction between two groups as between individuals.