It takes constant practice and reinforcement, in terms of our cognitive development of our brain. The younger you start a foreign language, the more likely you are to develop proficiency in it ... a student who is 18 has a leg up on someone who is 40, just like an elementary student will have a leg up on a college student, and may have a chance to achieve near-native proficiency.  -   Daniel Collins     Quotes
It takes constant practice and reinforcement, in terms of our cognitive development of our brain. The younger you start a foreign language, the more likely you are to develop proficiency in it ... a student who is 18 has a leg up on someone who is 40, just like an elementary student will have a leg up on a college student, and may have a chance to achieve near-native proficiency. Daniel Collins
 Brain