At the gym, I read the Can You Build a Better Brain? article in Newsweek about how to restructure our brains as we take on new things to learn. We need to repeat actions many times for our brains to change. For language learning, this means that we need to listen to the sounds of our target language many times for our auditory cortex to expand and to learn the correct pronunciation of words.
One of the strongest findings in neuroplasticity, the science of how the brain changes its structure and function in response to input, is that attention is almost magical in its ability to physically alter the brain and enlarge functional circuits. In a classic experiment, scientists found that when monkeys repeatedly practiced fine-tactile perception, the relevant brain region expanded, just as it does when people learn Braille or the violin. Similarly, a region of the auditory cortex expands when we hear a particular tone over and over.