The Brain and Bilingualism

My wife and I are raising our kids to be bilingual in English and Japanese, and it's interesting to observe how thought processes work in both languages. For the past four years, my son has attended a special experimental school that teaches the normal Japanese curriculum but with 70% of the classes in English, and as a result, his brain has gotten quite used to thinking in that language. When working through difficult math problems, for example, I'll hear him utter, "Oh, they're talking about lowest common denominator" because he's more familiar with that term in English rather than in Japanese. Or sometimes it'll work the other way: once he didn't know what "gravity" was in English because he'd learned the concept in Japanese and hadn't built the synaptic bridge between the two words. When I came to Japan, I somehow managed to learn the word muri (無理), meaning "not able to be done," by having it explained to me in Japanese. As the word embedded itself in my brain I got quite comfortable with its use, and I never had the need to connect the word to an English equivalent. It was about a year later when I realized that the word had a very simple English counterpart, which was the word "impossible." It amazed me that the two parts of my brain could work so independently of each other that I could learn a concept in one language without it being hooked up on the other side. And yet, this is what happens in the minds of children who learn two languages growing up: both are separate and only come together synaptically when needed.