Research of the human brain shows that we are set up to learn and grow at any age. An adults brain is capable of learning a language like any other skill. A study by Kwok et al., 2011 found that adults' brains can change quickly in response to practice in as little as 2 hours. One of the most convincing pieces of information in the information I have read states, "Adults can learn a second language to a high level of proficiency in the same amount of time it takes a baby to learn its 20 first words." An adults advanced cognitive abilities put them at an advantage compared to children who receive instruction just one hour per week. And when adults, like missionaries, were placed in a situation where they are immersed in the language, they acquired the language in 18-24 months. This is much quicker than a child learning language. Children have not finished their acquisition of basic grammar until the age of 4. I am convinced that an adults brain is just as capable of learning a language as a child's is. The only difference is in how the brain receives and stores the information.