ROBERT SIEGEL, HOST:
And now news about language development.
(SOUNDBITE OF BABY TALKING)
SIEGEL: In babies. Most babies don't utter actual words until after their first birthday. But according to a new study that's out this week as early as 7-months-of-age babies brains are already working on the mechanics of how to form words. They are rehearsing how to speak months before their first words. Patricia Kuhl is the lead author of the study. She's co-director of the University of Washington's Institute for Learning and Brain Sciences and she joins us now. Welcome to the program.
PATRICIA KUHL: Hi Robert. Thanks for inviting me.
SIEGEL: Let's first have you explain how you carried out this study about what's going on inside the brains of 7-month-olds.
KUHL: Well, first of all we had to have one of these wonderful new machines magnetoencephalography - MEG for short - what it allows is for the first time we can see inside the baby brain as the baby's doing something interesting - like listening to language.
SIEGEL: And you played them sounds over headphones. What did you see going on when you did that?
KUHL: As the brain listens to sound the baby's auditory areas aren't the only areas lighting up. It's also the areas that they use to talk - their motor-planning areas. It's as though the baby's rehearsing their next moves. They're trying to join the community of people who use their mouths in these funny ways to create sounds. And so here we see the babies at 7-months where on the outside you don't see anything - they're wide-eyed and they're looking at you and they love to listen to you. But what's going on in their little brains is the attempt to do it to, they want to be one of us. And that means they have to rehearse the mechanics of this pretty difficult signal to produce.
SIEGEL: You also write that exaggerated speech is helpful. Why?
KUHL: Well, we've been studying for some time this phenomenon that we call mother-ese or now parent-ese because both parents and everyone seems to do it. If I had a 2-month-er in my hand I'd be saying something like, hi cutie let's open those big blue eyes, you know, using these stretched out vowels and big excursions and pitch contour - and speaking quite slowly. Babies not only love to listen to that - their language development is zooming forward at a much more rapid rate. Languages at 2-years-of-age if you're exposure at 11 and 14-months is quite high, you have twice the number of words that you know when compared to children who are not hearing much mother-ese and not hearing that in face-to-face communication.
SIEGEL: I was just wondering - perhaps we could bring back little Zosha (ph) whom heard a few seconds of a moment ago. And you could tell us what would you say to this?
(SOUNDBITE OF BABY TALKING)
KUHL: First of all, I'd smile and say, you're adorable. I mean, that is such a wonderful sound. You can help but smile when you hear that. And you can see that that's, you know, those aren't clear words coming out - but that's just pure joy and the attempts to do what you're doing - which is to talk. And I think that drive that deep, deep social drive to communicate, to talk back, to volley when you serve, to go back and forth is really strong. And you can see it in their eyes but to see it in their brains - it was astounding to see that practice as the brains getting ready to make its next move.
SIEGEL: Well, I think you've helped make several people's ride home a little bit more fun this evening. Thanks for talking with us.
KUHL: Well, I hope so and thanks for having me Robert.
SIEGEL: That's professor Patricia Kuhl who is co-director of the University Washington's Institute for Learning and Brain Sciences. Her study, by the way, was published this week in the proceedings of the National Academy of Sciences. Transcript provided by NPR, Copyright NPR.