> But the study also showed that it is best to start by age 10 if you want to achieve the grammatical fluency of a native speaker Another angle that should be

> But the study also showed that it is best to start by age 10 if you want to achieve the grammatical fluency of a native speaker Another angle that should be considered is that, while children learn languages very quickly, they can 'unlearn' just as fast. One of my cousins spoke fluent Japanese as a young child. Then he moved to another country. A few years later he couldn't speak or understand Japanese anymore. I've since learned that this is very common.