A very good friend of mine posted a very interesting video one day:
If you don’t have the time to watch it (although I urge you to), the video is about how a slight change in the design of a bicycle will confuse you so much that you won’t be able to ride a bike anymore. And in order to ‘relearn’ how to do it, you somehow have to forget to ride a regular bike. Destin proves this is possible but it takes a very long time. He managed to learn to ride the ‘new’ bike in about nine months, but doing so, he forgot how to ride a regular bike. What’s interesting is that a child is able to do this a lot quicker (apparently, it took his son about 3 months). The conclusion of this exercise is that knowing does not equal understanding. Learning to learn a bike is an ‘intuitive’ process, meaning that your brain does the job for you and you don’t really know what it actually does.
What struck me about this short video is that language acquisition works in the same way. The acquisition of one’s mother tongue, that is. Just think about it. If somebody asks you about a certain grammar rule in your native language, do you know the answer instantly? You would probably have to think a bit. You would try to infer the rule from examples. And that is because you speak the language intuitively, the whole acquisition process that dates back to your early childhood was purely intuitive. At a basic level, you don’t even need to study grammar in school in order to speak your mother tongue. And if you hear a new word, you instantly know what to do with it (how to integrate it in a sentence, how to form the plural etc.). This is another case of ‘knowing without necessarily understanding’. You don’t know how your brain manages your native language.
This explains why it is so difficult to learn a foreign language after you have already acquired your mother tongue. The intellectual mechanisms involved are completely different. When you study a foreign language at a later age (but even as early as 8-9 years of age), you employ your analytical skills and not your intuitive skills. You constantly compare the words, structures and rules of the new language to those of your own. This means that speaking will involve less spontaneity and more ‘awareness’. You will not be able to actually ‘feel’ that particular language and you will always be aware that it is not actually yours. Furthermore, there will always be a certain degree of inertia which will prevent you from speaking it at a native level (think of accents, syntax, fluency). Sure, there are gifted people who manage to reach a near-native or even native level, but the majority will always struggle to a greater or lesser extent.
Clearly, the mental processes employed in learning to ride a bike are much less complex than those of learning a language. This is probably why, if you try hard enough (apparently very hard), you can instruct your brain to re-learn to ride a modified bike and thus forget to ride the regular bike. With languages it is much more difficult – if not impossible. There would probably need to be a traumatic event (God forbid) in order to wipe out one’s native language from one’s brain. But probably if you could erase the knowledge of your original mother tongue, you would be able to acquire a foreign language intuitively and thus speak it as your own.