Dear Science,

Is there an age limit to learning new languages? If so, does it apply only to spoken languages, as opposed to ancient or programming languages?

Aspiring Native Speaker

Science consulted his friendly local linguist and was introduced to the critical period theory of language acquisition—and poor Genie. Genie spent the first 13 years of her life locked inside of a room—without any sort of human contact. When eventually discovered by Los Angeles–area child welfare people in 1970, it became apparent, to their horror, that she could not speak any language. Despite years of attempts, Genie was only able to eventually offer short verbal answers like a two-and-a-half-year-old; her nonverbal communication improved far more so.

Linguists loved Genie. The critical period theory claims that primary-language acquisition has to occur before puberty; Genie was living evidence that the hypothesis was true. The theory claims that if you start learning a verbal language before puberty, you can become a native speaker. If you learn after that, your writing and grammar can be exemplary but you'll always sound a little off. The parts of the brain responsible for recognizing and categorizing different sounds start to lock down. Children raised with Asian languages lacking a distinction between R and L sounds, for example, who are not seriously exposed to English before puberty struggle later when learning to speak like native English speakers. Pat Kuhl, a scientist at the University of Washington, has done some cool work with babies around these questions.

Children learn language in ways that go far beyond mere imitation of their parents and others. Children create their own grammar rules—testing them with their parents and other people. Over time, these rules are tuned and pruned into fluency. Feeding into this is a genetically preprogrammed "universal grammar," an instinctual set of rules for verbal communication between people.

The critical period theory has been around for quite a while, since the 1960s, when proposed by Eric Lenneberg, and it's why exasperated linguists keep asking for foreign languages to be introduced to American schoolchildren before middle school. While most linguists today would agree the critical period theory is correct for the acquisition of a first language, there is far more controversy about the puberty timeline as a limit for proper learning of a second language. Everyone seems to agree earlier is better; the age boundary seems blurrier, however, when struggling through your second language.

Learning how to read and write a new language (as opposed to speaking it) seems to be easier on those of us who are long past puberty. So if spoken Mandarin is giving you too much grief, perhaps it's time to pick up some Python programming.

Verbally Yours,

Science

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