什么時候?qū)W習一門新外語不算晚？

Perhaps you've toyed with the idea of learning a second or third language. But as an adult, is learning a new language too monumental of a task to undertake?

Let's look at what we know about language development. Early childhood — infancy until age 5 — is a particularly sensitive period when children's brains are primed to learn language.

According to Thomas Bak, Ph.D., a neuroscientist from the Centre for Cognitive Ageing and Cognitive Epidemiology at the University of Edinburgh, children first learn sounds, and then acquire the basic rules of grammar. Then comes vocabulary, which continues to accumulate throughout life. (Microbiome, microagression, net neutrality, safe space, and Seussian are just a few of the 1000 new words that Merriam-Webster added in 2017.)

From birth through puberty, children learn language rapidly and efficiently due to their naturalbrain plasticity and cognitive flexibility. After puberty, however, language acquisition becomes progressively more difficult, and our ability to learn new languages steadily declines.

There's some individual variability in the age of this decline, Bak says, due to natural ability. But a slight decline does occur in all people at some point, whether it be in their 20s or 30s.

Nienke Meulman, who has published research on age and grammar acquisition effects on the brain, says the adage,"'The later, the harder' is definitely true, but there is no clear cut-off age." Even for late learners it is possible to become proficient in a second language, Meulman says.

Bak, who has conducted research on language and aging, tells Business Insider, "the thing which is most difficult to learn as we age is ... sounds." So while you may become more proficient in speaking and communicating in a second language other than your native language, if it's learned after puberty you won't ever speak with a local accent.

"Very often people are completely focused on the idea to sound like a local, but this is in fact the most difficult aspect," Bak says. While your pronunciation of a language will sound best if you learn it early, building your vocabulary and communicating well in a different language is attainable at any age.

Though it may get more difficult, the benefits of learning a new language are immense.

"Difficult is not a bad thing," Bak says. He compares language use to physical activity, where it may be more difficult to achieve physical health as you age, but the more you work out, the better off you are. And just as the benefits of exercise become more crucial as we age, so too do the cognitive benefits.

Because GPS and smartphones can do so much of our thinking for us, our mental acuity can suffer, especially as we age.

"It's not about making things easy, it's about making things worthwhile," says Bak. And his research supports the notion of how worthwhile language learning can be in later life, and that we can indeed learn all our life.

He tells the story of a woman he met when she was 92. With very little prior foreign language knowledge, she had began studying Russian at the age of 56. At age 75, she went on to write her Ph.D. thesis about Russian poets, and now at age 92 is one of the most acclaimed translators of Russian poetry into English.

"My main message is that it's never too late," says Bak. "The main message is about empowerment."

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你是否曾考慮過學習第二或第三語言?但對成年人而言，學習新語言是否太過艱難?眾所周知，兒童在嬰幼兒時期(0-5歲)格外敏感，他們的大腦非常擅長學習語言。

愛丁堡大學的神經(jīng)學家Thomas Bak表示，兒童首先學習語音，其次掌握基本語法規(guī)則，然后擴充詞匯量——在人的一生中，詞匯量會不斷地積累。從出生到青春期，由于天生的大腦可塑性和認知靈活性，兒童能夠迅速而高效地學習語言。然而，在青春期結(jié)束后，學習語言會變得越來越困難，我們學習新語言的能力會逐漸下降。

所有人都無法避免語言學習能力退化的現(xiàn)象，但具體年齡節(jié)點存在個體差異——也許是二十歲，也許是三十歲。因此，即便你很晚才開始學習外語，仍然有可能熟練掌握。

隨著年齡的增長，最難學習的部分是語音語調(diào)。因此，即便你能夠熟練運用第二語言進行交流，但如果這門語言習得于青春期之后，那么你將永遠無法掌握正宗的口音。很多時候，人們非常注重口音問題，希望說得像本土人一樣;但其實，這恰恰是最難的部分。別喪氣，雖然學習越早發(fā)音越好，但任何年齡都能夠積累詞匯量、并進行流利的交流。

盡管學習新語言越來越困難，但學習過程益處多多。我們可以將學習語言和鍛煉身體進行類比——隨著年紀的增長，我們越來越難保持身體健康;話雖如此，但你越鍛煉身體，身體狀況會越好。年齡越大，鍛煉身體越重要，鍛煉認知也是如此。如今，GPS和智能手機代替我們思考許多事情，這反而損害了我們的認知敏銳度。當我們?nèi)找嫠ダ蠒r，學習語言雖然困難，但卻能夠鍛煉認知。因此，“活到老學到老”這句話非常有道理。

Bak告訴我們，他曾經(jīng)遇到過一位92歲的老太太。她從56歲起開始學習俄語。75歲時，她完成了一篇關(guān)于俄羅斯詩歌的博士論文。如今，她是享有盛譽的翻譯家，負責將俄羅斯詩歌翻譯成英語。

記住，學習絕不言遲!