Speaking a second language is a great way to broaden your communication abilities. But many people assume that learning a second language is something they should have tackled as a child, that it becomes too difficult as they grow older. In actuality, children don't necessarily learn languages more easily than adults. Rather, there are certain parts of the language-learning process that are easier as children, while other parts are easier as adults.
When children are young, their brains are in the process of developing. They are malleable and spongelike, always changing and soaking up information. For this reason, learning a first or second language takes place without conscious thought. For children it's more like second nature. A study conducted by Dr. Paul Thompson at UCLA, for example, found that children use a part of their brains called the "deep motor area" to acquire new languages. This area of the brain is activated when you're walking, tying your shoe, or taking a sip of water; it controls unconscious actions. The fact that this same portion of the brain is employed by children when learning languages lead Thompson to conclude that language acquisition is a natural process, something that is second nature, something that a child doesn't have to actively think about. Adults, on the other hand, must think actively about learning a second language. For them it is not second nature, but an intellectual process. This is because an adult's brain has already formed--the circuitry and synapses have been wired to fit the parameters and pronunciations of their first language. Luckily, as an adult, you've already developed the capacity for intellectual learning.
Since adults are capable of grappling with language on an intellectual level, they are actually better suited for becoming proficient in a language more quickly than children. Often we think it's the other way around. We may, for example, observe a child saying a couple of phrases in two languages and conclude that he or she is bilingual. But David P. Ausubel, a linguist at the University of Illinois, points out that children have small vocabularies and use simple constructions to communicate their needs. Adults, on the other hand, communicate in much more complex ways and command very large vocabularies. This gives people the false assumption that children learn a language more quickly. In actuality, adults simply have more to learn to communicate on the same level that they communicate at in their first languages. Moreover, according to Ausubel, adults and adolescents are able to generalize and think in abstract terms. A child needs to hear a phrase time and time again to distinguish a recurring pattern. This type of discovery takes a lot of time and a lot of exposure. Adults can hear a phrase once and understand that that phrase can be universalized across the entire language. The same goes for grammatical patterns: an adult is more likely to realize that many of their first-language's patterns can be applied to the second language, whereas a child's brain has not developed the maturity to think in such abstractions and is therefore unable to make the same connections.
Aware of the differences in language-acquisition processes and aptitudes, experts have realized that teaching methods ought to differ, too. In order to teach a child a second language it is important to expose them to both languages at school and at home. Full immersion will help a child pick up on patterns more readily. Also, using mnemonic techniques like singing songs or having repetitive drills will help wire the new language and its pronunciations into a child's brain. Older language learners often get hung up on pronunciation but learn to understand the grammatical and syntactical patterns more easily. Therefore, adults should concentrate on getting the grammatical fundamentals down so as not to get discouraged by pronunciation difficulties. Once the grammar is down, the difficult specter of correct pronunciation can be slowly chiseled away at and refined over time.