¿Hablas español? Parlez-vous français? 你会说中文吗? If you answered, "sí," "oui," or "会" and you're watching this in English, chances are you belong to the world's bilingual and multilingual majority. And besides having an easier time traveling or watching movies without subtitles, knowing two or more languages means that your brain may actually look and work differently than those of your monolingual friends. So what does it really mean to know a language? Language ability is typically measured in two active parts, speaking and writing, and two passive parts, listening and reading. While a balanced bilingual has near equal abilities across the board in two languages, most bilinguals around the world know and use their languages in varying proportions. And depending on their situation and how they acquired each language, they can be classified into three general types. For example, let's take Gabriella, whose family immigrates to the US from Peru when she's two-years old. As a compound bilingual, Gabriella develops two linguistic codes simultaneously, with a single set of concepts, learning both English and Spanish as she begins to process the world around her. Her teenage brother, on the other hand, might be a coordinate bilingual, working with two sets of concepts, learning English in school, while continuing to speak Spanish at home and with friends. Finally, Gabriella's parents are likely to be subordinate bilinguals who learn a secondary language by filtering it through their primary language. Because all types of bilingual people can become fully proficient in a language regardless of accent or pronunciation, the difference may not be apparent to a casual observer. But recent advances in brain imaging technology have given neurolinguists a glimpse into how specific aspects of language learning affect the bilingual brain. It's well known that the brain's left hemisphere is more dominant and analytical in logical processes, while the right hemisphere is more active in emotional and social ones, though this is a matter of degree, not an absolute split. The fact that language involves both types of functions while lateralization develops gradually with age, has lead to the critical period hypothesis. According to this theory, children learn languages more easily because the plasticity of their developing brains lets them use both hemispheres in language acquisition, while in most adults, language is lateralized to one hemisphere, usually the left. If this is true, learning a language in childhood may give you a more holistic grasp of its social and emotional contexts. Conversely, recent research showed that people who learned a second language in adulthood exhibit less emotional bias and a more rational approach when confronting problems in the second language than in their native one. But regardless of when you acquire additional languages, being multilingual gives your brain some remarkable advantages. Some of these are even visible, such as higher density of the grey matter that contains most of your brain's neurons and synapses, and more activity in certain regions when engaging a second language. The heightened workout a bilingual brain receives throughout its life can also help delay the onset of diseases, like Alzheimer's and dementia by as much as five years. The idea of major cognitive benefits to bilingualism may seem intuitive now, but it would have surprised earlier experts. Before the 1960s, bilingualism was considered a handicap that slowed a child's development by forcing them to spend too much energy distinguishing between languages, a view based largely on flawed studies. And while a more recent study did show that reaction times and errors increase for some bilingual students in cross-language tests, it also showed that the effort and attention needed to switch between languages triggered more activity in, and potentially strengthened, the dorsolateral prefrontal cortex. This is the part of the brain that plays a large role in executive function, problem solving, switching between tasks, and focusing while filtering out irrelevant information. So, while bilingualism may not necessarily make you smarter, it does make your brain more healthy, complex and actively engaged, and even if you didn't have the good fortune of learning a second language as a child, it's never too late to do yourself a favor and make the linguistic leap from, "Hello," to, "Hola," "Bonjour" or "你好’s" because when it comes to our brains a little exercise can go a long way.
Hablas español? Parlez-vous francais? 你會說中文嗎? 如果你能回答 "si" , "oui" 或是 "會", 而且能用英文字幕觀看這部短片, 你就跟世界上大多數人一樣, 屬於雙語或多語的使用者。 除了「旅遊時溝通比較方便」 或是「看電影時不需要字幕」 這些好處之外, 通曉兩種或三種以上的語言, 表示你的腦袋,在㚈表和運作方式上, 與使用單一語言的朋友,有明顯的不同。 究竟什麼是「通曉」一種語言? 衡量語言的使用能力, 包含兩種主動能力:說、寫; 另㚈還有兩種被動方式:聽、閱讀。 雖然一個平衡的雙語使用者, 對於兩種語言, 具有相近的使用能力; 但是大多數的雙語使用者, 當初如何學習並運用語言, 有許多不同的方式。 根據個人所處的環境, 以及如何學習語言的方式, 通常可以把雙語使用者 分為三類: 就以加布瑞拉為例, 她在二歲時,跟著家人 由祕魯移民到美國。 她屬於「複合型」雙語使用者, 加布瑞拉只用一組概念, 同時發展兩種語言符碼。 當她開始適應新環境時, 也同時學習英語及西班牙語。 她有一個十幾歲的弟弟, 是屬於「對等型」雙語使用者, 他運用兩組不同的概念, 一面在學校學習英語, 一面用西班牙語, 跟家人、朋友溝通。 最後是加布瑞拉的父母, 他們是「從屬型」雙語使用者。 當他們學習第二種語言時, 需要透過母語進行翻譯。 上述三種雙語使用者, 他們至少都能精通一種語言, 無論是在腔調或是發音方面, 因此,一般人難以發覺 這三種類型的差異。 然而現在, 由於大腦成像技術不斷進步, 神經語言學家得以窺探 語言學習對於雙語使用者的大腦 產生何種影響。 大家都知道,大腦的左半部 主要掌管邏輯思考與分析, 而右半腦則掌管情感與社交活動, 雖然左、右半腦有所區別, 但並非完全獨立運作。 事實上,語言同時包括了 左腦與右腦的功能, 而隨著年紀增長, 大腦功能逐漸側重其中一邊, 這個觀點發展出 「關鍵時期」的假説。 根據這個理論, 兒童通常學習語言較快, 是因為大腦仍在發展, 因此仍具有可塑性, 他們可以同時利用 左、右兩邊的大腦學習語言; 然而,多數成人會偏向採用 其中一側的大腦來學習語言, 通常是左半腦。 如果這個觀點正確, 那麼從小就學習語言, 能夠更容易掌握 語言的社會和情感脈絡。 相反地,最新的硏究指出: 如果人們到了成年之後 才學第二種語言, 當他們遇到有關 新語言的學習問題時, 會呈現出較少的情緒偏見, 也會有較為理性的思考。 無論如何,當你學習新的語言時, 可以替你的大腦帶來明顯的好處。 有些好處,甚至可以看得見, 例如大腦灰白質的密度增加, 那裡包含了腦部 大多數的神經元和突觸, 而且學習第二語言時, 大腦部份區域會變得更活躍。 使用雙語的大腦, 持續不斷地接受強化訓練, 能夠讓一些疾病的發作, 例如阿茲海默症與失智症, 延遲高達五年之久。 關於使用雙語 有助於人類認知的觀點, 在今天看似理所當然, 但是對於從前的專家, 他們必定會大吃一驚。 在1960年代以前, 人們認為使用雙語 對於兒童的發展是一種障礙, 因為需要迫使兒童 花費精神去分辨兩種語言, 而這種觀點主要來自於 錯誤的研究。 最新的硏究顯示, 在跨語言測驗當中, 使用雙語學生的反應時間 與錯誤次數增加了 這個結果顯示, 學生需要更努力與專注於轉換語言, 這也使得前額葉腦區 不僅更加活躍, 而且能強化它的功能。 前額葉腦區的主要工作, 是進行決策、 解決問題,以及 在多重任務中進行轉換, 還有集中注意力, 同時排除無關的資訊。 雖然學習雙語, 未必能讓你更聰明, 但是可以讓大腦 更加健康、多元以及活化。 即使在你年幼時, 沒有機會學習第二種語言, 但是現在學習, 永遠不會太晚。 學習㚈語的第一步, 就是開始把"Hello", 轉換為: "Hola"、"Bonjour" 或是 "您好"。 只是小小的訓練, 就能對於大腦有所幫助。