When I lived in San Francisco in the early nineties, my son Andy who was only 2 years old at that time was able to speak or at least understood Chinese. I discovered it to my amazement once when I was picking him up from Mrs. Took, a Chinese lady who was babysitting him for only a few hours a week. Mrs. Took would say something to Andy in Chinese and Andy would respond by bringing his jacket to Mrs. Took so that she could put it on him. Andy, who was not big enough to zip up his own jacket, was still small enough to be able to learn Chinese from the Chinese adults and kids surrounding him a few hours a day without really trying.
Why is it that small children find it so easy to learn a language, any language, while most adults can’t do that?
Small children learn languages almost effortlessly, and the older they are, the more difficult it is for them to learn a language.
I used to have a friend named Vašek when I was growing up in the town of Český Krumlov in the southern part of Czech republic whose grandparents were German. Every summer his parents left him for 2 months in Český Krumlov with his grandparents. And every summer, Vašek would learn enough German to communicate easily with his grandmother who did not speak any Czech, only to forget his German during the rest of the year because he was not using it. But by the time he was about 13, his mother started complaining that the damn German language was making Vašek speak funny Czech and they made him stop speaking German. The poor grandmother had to learn some basic Czech in order to communicate with her grandson.
So Vašek eventually forgot every single German word he used to know, and Andy forgot his Chinese too, of course, because neither of them needed the language anymore.
Small children don’t really distinguish between a foreign and a “native” language. They absorb all useful linguistic information up until the age of about 13 like a sponge absorbs water, as they kind of throw all information into the same place in their brain where they can find it easily later if they need it again, just like they throw all of their toys into one place when they are done with them (usually on the bed or under the bed).
But things change when we enter puberty because once we hit the teens, our brain starts prioritizing and compartmentalizing information. This is because our brain “knows” that some information is more important and needs to be accessed immediately, while other information may or may not be important, and some information is probably useless. Our brain (or perhaps medulla oblongata) thus performs what lawyers like to call information triage: some information is stored in easily accessible partitions of our brain, some is stored a little bit farther away, and some is discarded.
Do you remember the telephone number that you used to have in the town where you used to live for many years up until 10 years ago?
I don’t because I don’t need it anymore. But I do remember my last four addresses going back more than twenty years, including the street number and the zip code. This is because I sometime needed this information, for example when I was filling out the form for credit report or checking out the real estate trends in the places where I used to live, which must be why my brain (or medulla oblongata) determined that this information should be stored in an easily accessible partition of my overburdened brain.
The partitioning and compartmentalizing of our brain continues throughout all of our life, which is why stroke victims or Alzheimer’s patients may be able to remember vividly the details of what happened 30 years ago, without having a clue as to what happened last week.
If we wanted to be able to learn foreign languages as effortlessly as children, we would have to either have no need for partitioning of information just like a two-year-old, or we would need to be able to control this partitioning. The former is no longer possible for adults when their brains are fully formed, the latter takes a lot of effort for the same reason, which is why most adults find it so difficult to learn a new language, and old people often find it impossible.
The only way to imitate the method that small children use to learn a language is by completely immersing ourselves in a new foreign language. Adults can do that too, for example by moving to a foreign country where they have to function in a different language, which will force even an adult brain to adapt to it pretty quickly.
But of course, repartitioning of that old brain of yours is a lot of work, and things can go wrong, just like during hard disk repartitioning.
Once you stop using your old language, the brain will start pushing the old linguistic information into nooks and corners where it may not be as easily accessible as it used to be.
But even if you don’t use your old language much for decades, which would be my case, the information is still stored there somewhere in your brain even though it may not be immediately accessible to you, and you will recognize it when you see or hear it, just like you are likely to recognize your telephone number from 20 years ago if you happen to see it somewhere.
So on the one hand, it is true that it is much easier for children to learn a new language than for adults. Children can do that almost effortlessly. But these little multilingual geniuses will then forget just as effortlessly in no time at all every single word of a language that is not needed anymore. You use it, or you lose it.
Adults who have to make a lot of effort to learn a new language are likely to keep the knowledge stored in a relatively permanent partition in their brain where it can be accessed precisely because the learning process is so painful and because it requires a rearrangement of the system that our brain uses for storage of information.