Learning Your Native Language
Do you remember learning your native language? Chances are, the answer is no. You began learning your first language well before you began to form long term memories. As a baby, you first began to understand snippets of spoken language. After that, you started to mimic what you heard, making word-like sounds that still had no meaning. Soon you learned to form words in English (or whatever your native language was) to make yourself understood. As the years went by, you learned more words and began to speak with correct grammar. All this happened for you more or less unconsciously. You might remember being a small child in preschool, but if you do, chances are good that you remember playing with your friends and singing songs. You probably don't remember learning that 'took' is the past tense of 'take' and other basic grammar points. You were able to learn a language easily as a child without even thinking about it.
Learning a Language as an Adult
If you have ever taken language classes as an adult, you are probably well aware that language learning becomes much more difficult as we age. Adults rarely pick up a language unconsciously. Instead, we have to study, study, study, learning complex grammar rules and practicing our pronunciation and listening skills as much as we possibly can. Many of us yearn to be able to learn language as easily as kids can, but, unfortunately, the days of easy language acquisition are over for most of us.
Children Learn Languages Faster
Why is language learning so much easier for children than it is for adults? It turns out that this question still doesn't have a clear answer, even among the scientific community. When it comes to human behavior, language is one of the most mysterious aspects of our lives. It's clear that there is a period during childhood that is good for learning languages, and that it becomes more difficult afterward. The areas of the brain that govern language learning become much less active as we age. Beyond that, the mechanism is still not well understood. What is understood is that children learn not only their native language but also foreign languages much faster than adults.
Learning Two Languages at Once
Children who grow up in an environment where multiple languages are spoken can seamlessly pick up the different languages, sometimes without even realizing that they are different languages. For example, children whose parents speak two different languages will learn to speak to Mom in one way and to Dad in a different way, but they do not understand these two modes of speech as different languages. Even more fascinating is the case of children who are raised in 'bimodal' households. A bimodal household is one where language is spoken in two different ways, for example spoken language and sign language. According to famous linguist Noam Chomsky, these children will learn both languages easily and won't even have a preference for one or the other!
Raising Multilingual Children
So what's the implication for parenting? Well, if you want your children to speak more than one language, no advice is more important than this: start early! The earlier children start learning a second or foreign language, the easier it will be for them to learn and retain that language. Sending small children to bilingual schools or enrolling them in extracurricular language study is one way to put them on the path toward being successful polyglots - people who speak multiple languages. But remember, no matter how early children start learning a language, they can lose their linguistic ability if they don't continue to use and practice the language as they grow. Language is like anything else: if you don't use it, you lose it!