Baby talk: It’s much more sophisticated than you think

Children do say the darnedest things. But the next time you chuckle at a toddler insisting “I weared my jacket,” consider the possibility that her grammar is perfect, just in another language.

In his new book, “The Infinite Gift: How Children Learn and Unlearn the Languages of the World” Charles Yang argues that children learn their native language through a process of trial and error, searching for the correct grammar by trying out other grammatical systems and discarding the ones that don’t fit. Double negatives, for example, while not commonly used in English, are de rigueur in Greek and Spanish, not to mention Chaucerian Middle English.

Yang, who recently joined Penn’s linguistic faculty from Yale, where he taught linguistics and psychology, isn’t saying toddlers are expert at every language under the sun. Rather, he’s building on Noam Chomsky’s vastly influential theory of universal grammar, which claims that babies are born with an innate understanding of language and grammar.

Yang, who moved into the field of linguistics after earning a Ph.D. in computer science at MIT, goes one step further, seeing language acquisition as an evolutionary process involving natural selection. “Only the grammar actually used in the child’s linguistic environment will not be contradicted, and only the fittest survives,” he writes. “In other words, children learn a language by unlearning all other possible languages.”

In English, Yang points out, we say, “it rains,” even though the subject is essentially “a fake subject, a placeholder.” Children under the age of 3 often say simply “snows” or “rains,” omitting the “fake subject” until they learn that in English it’s needed. “Kids are always perfect,” says Yang, smiling. “Maybe not in English, but in Chinese.”

Yang’s own son, Russell, now 6, has provided him with plenty of raw material. “We did jot down many of his sentences,” admits Yang, whose wife is also a linguist, and an entire chapter of the book is devoted to his first word, “wuckoo,” meaning (not so obviously) truck.

For parents who worry that their child is lagging behind in learning to speak or mastering complex sentence structures, Yang says, “If this view is right, they shouldn’t worry at all.” Though children may start talking on different schedules and vary in the speed with which they accumulate new words, learning language is a biological phenomenon, says Yang, and “children are infinitely better at learning languages than we are.” Our obsession with language learning, he adds, is a peculiarly western phenomenon. “In cultures where parents and kids have less interaction,” he says, “kids still learn fine.”

Charles Yang