紐約神經科學家喬 · 賀希最近發現若干證據，證實孩堂與成人在學習第二種語言時，所使用的大腦部位並不相同 · 他使用一具稱作MRI(磁共振顯像)的儀器來研究兩組有雙語能力的人他們的大腦 · 一組成員曾在孩量時期就學過第二種語言。另一組成員是在長大後才學第二種語言。這兩
組人都被安置在MRI掃瞄機中。這樣可讓賀希看到大腦哪些部位較會充血以及活動力較旺盛。他要求兩組成員回想他們前一天所做過的事’第一遍用一種語言回想’第二遍用另一種語言回想。他們不可大聲說話，因為任何動作都會導政掃瞄中斷。
賀希仔細端倪大腦的兩個語言中心區—一為布羅卡區’一為維尼克區’一般相信前者可控制語詞的產生 · 而後者則處理意思 · 他發現雨組人不論用何種語言說話’都會使用維尼克區的同一部位 · 不過’他們如何使用布羅卡區時就有差異了 ·
從小就學第二種語言的人不論使用哪一種語言’都會運用到布羅卡區的同一部位。長大後才學第二種語言的人在使用該語言時會運用到布羅卡區的某特定部位——這個部位鄰近啟動他們學母語
時的那個部位。
賀希如何解釋這樣的差異呢?他相信語言第一次在孩童大腦內設定時，大腦會把各種語言全都混雜到同一區 · 不過設定一旦完成’大腦另外一個區域會接管新的語言。另一種可能性就是我們小時候跟我們長大時學語言的方式會有所不同 · 賀希認為媽媽會用不同的方式如(觸摸 · 聲音及視覺等)教小寶寶說話 · 這跟坐在高中的課堂上是有相當差異的。
Joy Hirsch, a neuroscientist in New York, has recently found evidence that children and adults don't use the same parts of the brain when learning a second language. He used an instrument called an MRI (magnetic resonance imaging) to study the brains of two groups of bilingual people. One group consisted of those who had learned a second language as children. The other consisted of people who learned their second language later in life. People from both groups were placed inside the MRI scanner. This allowed Hirsch to see which parts of the brain were getting more blood and were more active. He asked people from both groups to think
about what they had done the day before, first in one language and then the other. They couldn't speak out loud, because any movement would disrupt the scanning.
Hirsch looked specifically at two language centers in the brain-Broca's area, believed to control speech production, and Wemickes area, thought to process raning. he found that both groups of people used the same part of Wemicke's area no matter what language they were speaking. But how they used
Broca's area was difterent.
People who learned a second language as children used the same region in Broca's area for both languages. People who learned a second language later in life used a special part of Broca's area for their second language-near the one activated for their native tongue.
How does Hirsch explain this difference? He believes that, wher. Ianguage is Iirst being programmed in young children, their brainsrnay mix all languages into the same area. But once that programming is complete, a different part of the brain 1nust take over a new language. Another possibility is simply that we may acquire languages differently as children than we do as adults. Tlirsch thinks that mothers teach a baby to speak by using different methods such as touch, sound, and sight. And that's very different from sitting in
a high school class.
