Sci's terrible at languages. TERRIBLE. In my time, I've successfully mastered English, and attempted to master four other languages (five if you count a brief foray into Elvish when I was 15, but that doesn't really count) in my time. I have failed at ALL of them. Every once in a while I would achieve some semblance of competency, but there's no doubt that either I didn't start early enough, didn't try hard enough (two semesters of immersion definitely weren't enough), or there's only one language for this geek.
But what about people who DO learn more than one language? For those who learn as adults, it's often an extremely hard won skill. For those who learn from early childhood to mid adolescence, it's often a little easier. But no matter when it happens, it's an impressive skill. Those learning a second language will master additional tens of THOUSANDS of words along with the ones from their first language.
Two languages, but you've only got one brain. And that brain only have one major language circuit. Right now, scientists think that people who are bilingual use processing in their major language circuit to monitor and to control their FIRST language, so it doesn't butt in on their second (or third, or fourth). We know that some people are better at learning a second language than others. But what makes them different? Is it a different in your anatomy (which could depend on several factors, including genes, environment, development, etc), or is it just training? And then, can training influence your anatomy?
Tan et al. "Activity levels in the left hemisphere caudate–fusiform circuit predict how well a second
language will be learned" PNAS, 2011.
Reading in your second language is a complex task that requires more than you might think. If you are not fluent, often the word has to pass through your first language and get translated in your brain. You begin to have voluntary control over the second language. But as you become better, you keep your voluntary control over speaking your second language, and ADD the inhibitory control over your FIRST language, so that you aren't producing words in two languages at once. But where and how does this happen? And what makes some people better at it than others?
To look at the anatomy behind the learning of a second language, the scientists took a group of 10 year old kids. The kids were all Chinese, and in the same school system, being taught English as a second language at the same level of difficulty. They had all started learning English at age 6, and weren't yet proficient. They looked at them once, and then looked at them again one year later. Each time, the kids were given a reading test in English, and then they were placed in an MRI. While they were getting scanned, the kids were given English real words (like bucket) or English nonsense words (like guge), and had to identify what was a real English word and what was not. One year later, they were given the same test, at the reading level they should have reached one year later.
Obviously they found activity in a bunch of brain regions implicated in language processing. Areas like the inferior frontal gyrus (containing Broca's area), lingual gyrus (which is actually called that because it's apparently shaped like a tongue. I don't see it, but whatever. Also it helps in recognition of words), and parahippocampal gyrus.
But what they wanted to know what whether any of these regions were correlated with the reading ability of the kids, and more importantly, with how much they had progressed after a year. And two of them were: the caudate and the fusiform gyrus.
You can see here the two areas that showed higher activity correlated with better second language reading skills. This was at time 1. One year later, they brought them back, and the correlation persisted:
You can see there that the activation in the caudate was actually stronger at the year mark. Here, the activity level also reflects how much the kids had improved in their second language knowledge. This activation difference (higher activation and better reading skills) wasn't there when the students were working in their primary language.
What this shows is that people who have high activity in these brain areas MAY be better able to learn a second language than those who have less activity. And this ALSO means that the activity in the brain when reading in a second language is different from that of reading in your primary language.
Caveat emptor, obviously. We don't know if maybe some of those kids were getting outside help on their language skills before the test began. It's possible that the activation of the fusiform and caudate correlates with skills in a second language, but can't PREDICT how well you do in a second language. In order to really see that, they would have to scan the kids before they learned a second language at all, and see what the activation pattern looked like then, and look again over the time they learned the language (and I bet you someone is on that study already). It would also be interesting to see if this is something that some people have, or can it be the result of training?
But what I really like about this study is that it shows that learning a second language really does require an alternate path through the brain, correlating only with that second language, not with the primary language. It would be REALLY interesting to see how brain activation changed as people become FLUENT in their second language. Does it always take this different processing path through the brain? Or as you become fluent, do the two paths begin to appear more similar?
If this does turn out to be predictive of the ability to learn a second language, it might be useful in knowing who might need extra help when they need to become bilingual. I can tell you I'm probably lacking some extra activity in my fusiform and caudate. My continuing attempts to learn French may need more training, or I may just be stuck monolingual. 🙁
Tan LH, Chen L, Yip V, Chan AH, Yang J, Gao JH, & Siok WT (2011). Activity levels in the left hemisphere caudate-fusiform circuit predict how well a second language will be learned. Proceedings of the National Academy of Sciences of the United States of America, 108 (6), 2540-4 PMID: 21262807