Very young children are said to be like sponges. They absorb information and learning from the world around them with seemingly unrivalled ability. It follows, therefore, that they will be able to reach fluency in a second language much more easily than older children, and certainly adults.
In fact, there’s a definite window in childhood when it is considerably easier to acquire a second language, certainly with fluency. Researchers disagree how long that window remains open, but some say it reaches its peak by around 6 or 7 years old. After this point it is understood to be much harder to learn a second language, and considerably harder to gain fluency in it.
Why is this so?