小孩子打小学外语好不好？

郑风田 陈雪 中国人民大学

小孩子是不是应该打小就开始学习外语？什么时候学习合适？这个问题一直困扰着老师、家长和研究者。一般人认为学外语应该从娃娃抓丰收，学习当然是越早越好；但也有很多老师却持反对意见，认为小孩子过早学习外语，容易在两种语言的转换中产生很多迷惑，最后甚至连母语都没有学到位。最近知名学术期刊PNAS（Proceedings of the National Academy of Sciences）发表的一项相关研究，认为小孩打小学习外语还是蛮有益处的，该文章详细阐述了双语学习会如何影响小孩子的大脑发育和思维方式，以及在什么情况下学习外语才有用。这篇文章也是“ECONOMIST”有关大脑研究进展的专辑的一部分。

小孩子打小在双语环境里成长，可以提高大脑“执行能力”？

“执行能力”通常被认为是反映一个人认知能力的一个重要指标。它包括组织，计划，优先安排各类活动，注意力转移以及克服习惯性反映的能力等。Agnes Kovacs and Jacques Mehler两位研究者在意大利的的里雅思湾的研究发现: 在双语环境下长大的孩子“执行能力”更强。

的里雅思湾居住着很多斯洛文尼亚的居民，双语现象在这个城市十分普遍。在试验中，两位研究者选择了40个7个月大的婴儿作为观察对象，这些孩子中有一半在仅懂一种语言的环境下长大，另一半则在双语环境下成长。研究者先给这些孩子念一堆任意编造的单词，然后给他们看一个出现在屏幕的玩偶，随后改变玩偶的位置以及单词，观察这些孩子的反应可以发现：在双语环境长大的孩子更容易适应这种改变。

走出误区：此“双语”非彼“双语”

但必须指出的是，双语环境能够帮助小孩子提高大脑执行能力的一个前提是，这些小孩子都生长在天然的双语环境，他们必须要在同一个环境下同时学习两种语言，或许这才是执行能力提高的关键。如果我们强制性创造出一种“人工双语环境”，让小孩子在家学习一种语言，在学校学习另一种语言的话，谁也不敢保证会有同样的效果。

（编译者郑风田为中国人民大学教授；陈雪为中国人民大学硕士生）

Twice blessed

Apr 16th 2009
From The Economist print edition

Bilingual babies are precocious decision-makers

WHETHER to teach young children a second language is disputed among teachers, researchers and pushy parents. On the one hand, acquiring a new tongue is said to be far easier when young. On the other, teachers complain that children whose parents speak a language at home that is different from the one used in the classroom sometimes struggle in their lessons and are slower to reach linguistic milestones. Would 15-month-old Tarquin, they wonder, not be better off going to music classes?

A study just published in the Proceedings of the National Academy of Sciences may help resolve this question by getting to the nub of what is going on in a bilingual child’s brain, how a second language affects the way he thinks, and thus in what circumstances being bilingual may be helpful. Agnes Kovacs and Jacques Mehler at the International School for Advanced Studies in Trieste say that some aspects of the cognitive development of infants raised in a bilingual household must be undergoing acceleration in order to manage which of the two languages they are dealing with.

The aspect of cognition in question is part of what is termed the brain’s “executive function”. This allows people to organise, plan, prioritise activity, shift their attention from one thing to another and suppress habitual responses. Bilingualism is common in Trieste which, though Italian, is almost surrounded by Slovenia. So Dr Kovacs and Dr Mehler looked at 40 “preverbal” seven-month-olds, half raised in monolingual and half in bilingual households, and compared their performances in a task that needs control of executive function.

First, the babies were trained to expect the appearance of a puppet on a screen after they had heard a set of meaningless words invented by the researchers. Then the words, and the location of the puppet, were changed. When this was done, the monoglot babies had difficulty overcoming their learnt response, even when the researchers gave them further clues that a switch had taken place. The bilingual babies, however, found it far easier to switch their attention—counteracting the previously learnt, but no longer useful response.

Monitoring languages and keeping them separate is part of the brain’s executive function, so these findings suggest that even before a child can speak, a bilingual environment may speed up that function’s development. Before rushing your offspring into Tongan for Toddlers, though, there are a few caveats. For one thing, these precocious cognitive benefits have been demonstrated so far only in “crib” bilinguals—those living in households where two languages are spoken routinely. The researchers speculate that it might be the fact of having to learn two languages in the same setting that requires greater use of executive function. So whether those benefits accrue to children who learn one language at home, and one at school, remains unclear.