According to Snow (1983), neurolinguistic explanations are not adequate to prove the presumption that children are
superior in second language learning. Successful language learning is more a result of interaction with native speakers
and being unsuccessful is very much related with “social, cultural, or economic barriers to contact with native speakers”
(p. 146). She (1983) believes that, adults are better language learners, because they are also better in most of the other
learning tasks, when compared with children. This is mostly because of the differences in the cognitive development of
children and adults. In addition, adults have more world knowledge and language experience than children.
In another study, Fathman (1975) compares younger children with older children to see if there is a difference in the
acquisition rate of English grammar structures among younger and older children, and the order of the acquisition of
these structures. The results showed that, the rate of learning changes with age; however, order of acquisition did notdiffer among both groups. However, younger children, preteens, achieved significantly higher ratings in pronunciation.
According to Fathman (1975), these differences may be a result of maturational, physiological, or environmental factors.
She argues that there might be different critical periods for different aspects of a language. Accordingly, during preteen
years children have the ability to discriminate, imitate or interpret sounds better, whereas, after adolescence they become
better at understanding rules, memorizing structures and making generalizations.
Since most of the studies on critical period hypothesis are not consistent with each other, Krashen, Long, and
Scarcella (1979) brings a different argument. The claim is that, there are three points where these studies become
consistent:
1) When the time and exposure is the same adults proceed faster in early syntactic and morphological development;
2) Older children surpass younger children in early stages of morphological and syntactic development, again, when
time and exposure are the same;
3) Learning a language in a natural context during childhood results with higher proficiency when compared to those
who start learning as an adult.
Krashen , Long, and Scarcella (1979) supports the idea that adults and older children are generally faster in acquiring
a second language than children “(older-is-better for rate of acquisition)”, but children are superior in the ultimate
attainment in second language acquisition “(younger-is-better in the long run)” (p.574). The best predictor of ultimate
attainment is the age of arrival in the target language speaking community. It has been found that children become more
proficient in second language proficiency, because of their age on the arrival, but after a certain period of time their
length of residence do not become a distinguishing factor.
The studies concerning the adult / child differences are usually short term studies, and such studies showed that
results are superior to children. The studies comparing older and younger children are again short-term studies which
showed that if both groups are exposed to second language for the same period of time and in natural environments
older children learn syntax and morphology faster. In addition, in formal environments, when older children are
compared with adults, it has seen that older children surpass adults in morphology and syntax in about a year. Other
studies comparing children, learning a second language in formal environments showed that those who started school on
a later age, caught up with the ones who started earlier. (Krashen, Long, and Scarcella, 1979) This might be because
younger learners acquire at a much slower pace, and since older ones have more developed cognitive skills they are able
to catch up with them by learning fast.
There are also counter arguments to Krashen’s evaluation of the previous CPH studies. In a recent article by
Marinova-Todd, Marshall, and Snow (2000) three misconceptions about the relationship of the age of the language
learner and the L2 learning is discussed through review of the literature. According to the researchers, first, it is
misinterpreted that the ultimate attainment is gained by children since they learn quickly and easily. They argue that, in
fact, this was not the case and that literature shows examples of older learners learn more than younger learners when the
time is kept constant and actually younger learners learn more slowly and with more effort.
Second, the researchers claim that “neuroscientists have often committed an error of misattribution, assuming that
differences in the location of two languages within the brain in speed of processing account for differences in
proficiency levels and explain poorer performance of older learners” (p. 14). However, Marinova-Todd, Marshall, and
Snow (2000) argue that available data is not adequate to guess the ex