LINGUISTIC GENIUS OF BABIES
"Patricia Kuhl shares astonishing findings about how babies learn one language over another -- by listening to the humans around them and "taking statistics" on the sounds they need to know. Clever lab experiments (and brain scans) show how 6-month-old babies use sophisticated reasoning to understand their world." - Source
Of course it easier to learn a language when you are younger, especially when you are a baby. What do you do besides eating, playing, exploring, sleeping, crying and ______?
However, I don't agree with the diagram above, because I believe it is much more to it than simply getting stuck in the age thingy about learning a language. No doubt human being's ability to acquire a new language declines with age to some extent, but there are many more factors to learning a language than just the decline of the brain, which could vary dramatically from person to person, depending upon how they use it during their lifetime.
What about interest and passion to learn a language? For example, if a 30 year old dude has the interest and passion to learn a language, I am pretty sure he or she will learn a language much faster than a 3 year old kid, especially if given the same amount of time to achieve it.
Perhaps the brain power has declined, but by using learning and thinking skills acquired fused with passion and interest... No contest!
Well, that is my opinion, and I don't have a Magnetoencephalography (MEG) to prove it. Neither am I a linguist (and I am crappy at learning languages, too!), but I have met passionate people my age, or older that have a gift for learning languages really quickly. So, age might be one factor, but the interest and passion to learn fused with effective learning methods, I am pretty sure we can continue to learn new languages pretty well until we expire :)
What do you think?