1. You will confuse a child by raising it with two or more languages
This is an old belief prevalent in monolingual countries that has almost become political. Rest assured that your child's little brain has more than enough horsepower to cope with two languages or more without affecting the dominant language. This has been well proven by decades of research and countless families around the world, including the many bilingual counties where multilingualism is the norm, not the exception -- such as Canada, Belgium, Switzerland, and Finland, just to name a few.
2. Bilingual maybe, but more than two languages doesn't work
Considering how much babies have to learn in their first 3-5 years, another language doesn't really add much to the load. As long as they get consistent interaction, they will have no trouble learning more than one language.
Practical examples show that it's usually only when more than four languages are taught simultaneously that it starts to be difficult to provide the child with enough exposure in all of the languages. However, it really depends upon the parents, not the intellectual capacity of the child. In some cases, getting enough exposure to two languages can be challenging enough. But there is no reason whatsoever to believe that learning more than one language is anything but a positive experience for your baby.
3. Learn one language properly first and teach other languages later
This is not only wrong, but totally counterproductive. After having already learned one language, it takes effort, more interaction, and motivation to learn a second language. Studies have concluded that learning them simultaneously is magnitudes easier for both baby and parents.
4. Your child will only mix the languages together
Yes, some mixing will occur, but it is both harmless and temporary. As the child increases her vocabulary in each language, this phenomenon automatically disappears, just as a monolingual child will automatically fix mistakes after correct usage is learned. For example, children who are only learning English often begin by saying, "Me want" rather than "I want." Eventually, they learn what is correct. The same is true of multilingual children. Of course, the less you mix the languages yourself and the more consistent you are when speaking to your child, the less your child will mix.
5. Oh, don't worry, they'll pick it up in no-time!
If people think children should only be exposed to one language because they believe that's all they can handle, the opposite myth exists too. People sometimes think any exposure is enough, even a minimal amount like a play group once a week, watching TV or buying dolls that talk a foreign language. "Children need to be exposed to a different language for at least 30 percent of their waking hours to become bilingual." says Fred Genesee, a professor of psycholinguistics at McGill University in Montreal. "Less exposure may allow the child to comprehend but not speak a second language. Learning a second language is simple for children, relative to adults," he said. "But it won't happen overnight."
6. At this age, becoming multilingual is too late
No such thing. Children can always learn another language, at any age -- as can adults. Granted, it is easier during the early critical period. But, creating a more stimulating learning environment will jump start your little language student no matter when he starts.
7. Reading and writing in several languages? Some barely manage one
Sad as it is, illiteracy is the norm rather than the exception in this world. However, multilingual children are nearly always better at reading and writing than their monolingual friends. Research supports what many parents have long felt, that multilingual children have a better developed linguistic understanding.
8. No one else we know grew up knowing more than one language
Well, isn't it about time, then? All jokes aside, family pressure is not to be underestimated. Be firm, patiently explain why it makes sense for you, and make your own choices for your child. Remember that whatever advice others give you, you are ultimately the one responsible. Reason and hard facts generally stand the test of time better than mere opinions about your child's well-being.
9. Multilingualism is nice but uncommon
Estimates suggest that 75% of the world's population speaks more than one language. That means that despite the fact that most western cultures are monolingual, the majority of the world is multilingual. Many children learn one or more regional or tribal language at the same time they learn the official language of the country where they live.
10. You should stop if your pediatrician tells you it's not a good idea
Well, this depends. If there are legitimate developmental concerns, always consult a specialist. Most pediatricians only received training in language development for monolinguals, and in most countries, this aspect of a physician's training is minimal. Chances are, your pediatrician is no expert on linguistics research, bilingualism, or multilingual child development and is operating only from opinions, just as someone outside the medical field.