Almost everybody agrees it is never too early to start learning a foreign language- From the moment they come out of the womb (and, some experts believe, even before), babies have a natural ability to learn, and can start familiarizing themselves with a foreign language, naturally and unconsciously.

The first three years of a child's life are now believed to be a vital period, when the foundations for thinking and learning, among others, are set. Babies, and very young children, learn a second language as easily as the first, through sight, taste, smell, sound and touch.

New research from Bristol University even claims that babies who hear foreign speech in their first nine months of life pick up languages faster at school or as adults.

So, there is little doubt that "early" is "good", when it comes to learning a second language.

One of the questions I've seen a lot of discussion on recently, however, is, what is the latest one can start learning a language and still expect to sound native? That is to say, how long does this window of opportunity for language learning last?

While it is not clear that the window of opportunity actually closes, there is a degree of consensus among experts that there is an "optimal" time for language learning.

Some researchers insist that second language acquisition skills peak at or before the age of 7 or 8. More recent research claims that this window extends through puberty. 15 is often cited as the magic number, as adolescents who learn a foreign language before they turn 15 tend to have a better, almost native-like, pronounciation in this second language.

What those studies do not always say, is that there are many other factors, besides age, influencing the level of proficiency in a second language. Things like personality, self-confidence, but also motivation, need and opportunity, all play a big role in the final outcome.

And, of course, this is not to say one cannot learn a foreign language later on, even as an adult. We love to hear stories of people of all ages who have been successful in mastering a language, and learning how they did it and what worked for them.