Science / Medicine : For Children, It’s a Piece of <i> Gateau</i>
Learning a second language is a struggle, at least for most adults. It’s likely you’ll be pegged as a foreigner no matter how many hours you slave over flash cards and Berlitz tapes. In irksome contrast, children learn new languages--including their native tongue--perfectly and without apparent effort. This difference, long observed informally, has recently been confirmed in a number of psychological studies that have important implications about the structure of the mind.
“If you wait until puberty or adulthood, you’re going to speak with an accent,” said Peter Eimas, a psychologist at Brown University. His work has shown that not only pronouncing the sounds of a language but also hearing them correctly depends on exposure to that language early in life.
Eimas’ work supports what is known as the “critical period hypothesis”--the idea that puberty represents a deadline for full mastery of language.
Psychologist Elissa Newport at the University of Rochester and colleague Jacqueline Johnson of Cornell University tested a group of immigrants who had been speaking English for many years. Their subjects--native speakers of Chinese and Korean chosen from a university campus--were asked to judge whether tape-recorded English sentences were grammatically correct.
Newport and Johnson discovered differences between those who immigrated to the United States before and after puberty. Those who were exposed to English during childhood had a better grasp of grammar than later learners, despite the fact that early and late learners had been living in the United States for the same length of time--on the average, just under 10 years.
In the long run, their research confirms, children are better than adults at learning a second language. This jibes with previous work by Newport that suggests that all forms of language learning are subject to a deadline at puberty.
While most psychologists now accept the notion of a critical period, there is controversy about what causes it. A common view is that puberty is linked with changes in the part of the brain responsible for language learning.
But Newport suggests an alternative, noting that late in childhood, language learning abilities are diminishing at the same time that most other mental abilities are improving. Newport’s hunch is that this may not be a coincidence. She speculates that the language learning faculty itself might not deteriorate. Instead, the loss of language learning capacity could be, paradoxically, a side effect of better general information processing.
If Newport is right, some conventional views may be upset. For example, if one can figure out what fragments of speech a young child perceives, these same fragments could be provided to adult learners in lieu of their ordinary input. What ought to happen, Newport predicted, is that such adults will learn a language as well as early learners.
