When I began working in audiology (in the age of the dinosaurs) we did not think it was possible for a child with a significant hearing loss to learn a second language. When families came who were not primary English speakers, we told them they had to talk to their child in English if they wanted her to succeed in school. We were wrong. The data on bilingual learning is clear. Little brains are capable of learning multiple languages if they are exposed.
What should parents speak?
Parents should be encouraged to speak what ever language they are comfortable speaking. Why? Because we want children to have a very rich language experience. If parents are encouraged to speak a language they are not comfortable with, the complexity of the language will be limited and, therefore, what the child hears will be limited. Anyone who has tried to learn a language as an adult will know what I mean. I have some ability to communicate in Italian which I started to try and learn a few years ago, but it is really basic. (Not a good language model.) The languages I heard as a baby are much better developed in my brain. If each parent is comfortable in a different language, they should speak the language they are comfortable speaking. In this way, they will be exposing their children to a rich and complex language which will help the child to develop their auditory brain and expand language and literacy.
Are bilinguals smarter?
There was an article in the New York Times Science section a few weeks ago entitled Why Bilinguals are Smarter. The author (Yudhijit Bhattacharjee) postulates that knowing two languages has dramatic effects on cognitive development. Research indicates that both languages are active in the brain all the time, so when speaking one language, the brain has to deal with this, giving the mind a “workout” that strengthens cognition. Research has indicated that bilinguals are better at mental puzzles. Bilingualism is reported to improve executive function which helps to solve problems, and ignore distractions. Research by Tamar Gollan at the University of California, San Diego has shown that elderly bilinguals are more resistant to onset of dementia than monolinguals.
Is there a down side?
Well, it takes work to learn a second language. In addition, children with hearing loss need more exposure to learn any language. So learning a second language can be an arduous task. If the bilingualism is happening naturally in the home with one parent speaking one language and another parent, or the nanny, speaking another language, we can assume that the child will get rich exposure in both. What about learning a second language in school? This may be a little more difficult. If a child is studying a second language, we need to be sure that she is getting sufficient exposure to the language and not just a little bit of exposure if we her to succeed. Yes, it may be a little difficult, but it may also be work the effort.