AA: I'm Avi Arditti with Rosanne Skirble, and this week on Wordmaster: why forgetfulness might actually help in learning a second language.

RS: Ben Levy is a graduate student in the Psychology Department at the University of Oregon, studying an area called inhibitory control and long-term memory.

BEN LEVY: "When people are actually exposed to a situation where they have to be immersed in a foreign language, after that immersion process, when they return back and try to speak their first language, they actually report difficulty speaking their native language. And while linguists had known about this for a while, this first-language attrition, there wasn't really any good explanation about why it occurred."

AA: "Take us through the process, how does this work with the brain?"

BEN LEVY: "What we did was we brought in undergraduates from the University of Oregon who are native English speakers, who are in the process of acquiring a second language, which is Spanish in this study. And what we did is we just showed them pictures of objects. So these would be very simple objects that they should know in both languages, things like a broom or a snake or a spoon.

"And whenever the object was presented in green, we asked the subject to simply come up with the English word for that object as quickly as they could. However, whenever the object was presented in red, we asked them to come up with the Spanish label as fast as they could.

"Now, what we were really interested in here is what happens to the corresponding English word for the object after you've repeatedly named it in Spanish. So if you see a picture of a snake on the screen twelve times, and every time it's presented in red and you have to say culebra as fast as you can -- which is the Spanish word for snake -- what happens to that English word snake?"

RS: To find out, Ben Levy says, the students had to take a final test in the form of a rhyming exercise.

BEN LEVY: "We gave them a word that would rhyme with one of the words they saw earlier, and we asked them to come up with the word they saw earlier that rhymed with it. So we might present them with 'brake' and say 'what did you see earlier that rhymed with that?' And if the subject can correctly remember the word, they're going to say snake out loud.

"And what we find is that -- the more often you name something in English, of course, the easier it is to come up with these English words on this final test, right? That's obvious. But the more surprising part is, the more often you actually named the thing in Spanish, the harder it is for you to generate the corresponding English word, suggesting that that word has actually been inhibited. That verbal label is harder to come up with after having practiced the corresponding word in the second language."

RS: "Now, did that surprise you?"

BEN LEVY: "Well, that's what we were expecting, coming from our background. But I think that most people would be surprised by a finding like that. You know, at first, it may sound like it is a scary and bad thing [that] you might be losing your native language by acquiring a second one. But, in fact, I would argue that this is actually an adaptive good thing.

"You can think about it this way: As a second language speaker, particularly when you're in one of these difficult immersion situations, what's going on in your mind is sort of like a race. So you have this native language word and you have this second language word which is much weaker. And as your mind is trying to think of the name for this object out there in the world, or some concept you're trying to express, you have a race between those two verbal labels. And what's going to happen in that race?"

AA: "The stronger is going to win?"

BEN LEVY: "The stronger is going to win, right? Now if you're in an immersion situation where you really need to express yourself, you don't want that stronger one to win anymore. You want the weaker one to win. So what we're saying is that what the speaker does in that situation is actually inhibits that native language word, so it won't always win the race. So that that second language word can actually have a hope of being retrieved."

RS: "Well, there's new hope, is what you're saying here, is there's new hope for those learning a second language."

BEN LEVY: "Uh-uh. Of course, the concern is that then we might actually have this permanent loss of our first language. But I think as long as somebody goes back and practices the first language after learning the second language, most of these any kind of losses in the first language will be recovered.

"So there's actually research on this that six months later, after college students who go travel abroad, come back and begin speaking their language again, any losses that they had from that time spent abroad are fully recovered within six months. So as long as you go back and speak that first language again once you go back, there's no problem at all. You can easily recover from these?"

RS: "Well, that's good."

AA: "Now, do you speak any other languages?"

BEN LEVY: "Uh, not well. Personally I took Spanish for many years, then actually a few years ago I married a woman who speaks German among her family. And so I decided that I wanted to learn a little bit more German myself, so I could sort of be in on what they were talking about. And so I started taking German classes here at the university.

"And what I actually found was, when I was learning German, I didn't have so much problem with English, because I was of course going back to speaking that outside of the classes. But I did find that I actually started to lose some of my Spanish. And it's much more difficult for me to go back and think about things in Spanish now after having learned German."

RS: Researcher Ben Levy at the University of Oregon. His study, with Professor Michael Anderson, appears in the January issue of Psychological Science.

AA: And that's Wordmaster for this week. You can learn more about learning English at our Web site, voanews.com/wordmaster. And our e-mail address is word@voanews.com. With Rosanne Skirble, I'm Avi Arditti.