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Humans can talk. I'm not always the best ad for it. But we can. Monkeys and apes can't talk. But what if they could? NPR's Nell Greenfieldboyce reports on a new study that explored what monkeys' voices would sound like if they had humanlike brains to help them speak.
NELL GREENFIELDBOYCE, BYLINE: Did you ever see a movie called "Rise Of The Planet Of The Apes?"
(SOUNDBITE OF "RISE OF THE PLANET OF THE APES" FILM)
GREENFIELDBOYCE: It came out a few years ago. And in it, a chimp named Caesar gets exposed to a brain-enhancing drug. Later, he escapes from a cage and is grappling with a guard, who tells him to get away.
(SOUNDBITE OF FILM, "RISE OF THE PLANET OF THE APES")
UNIDENTIFIED ACTOR: (As security guard) Take your stinking paw off me, you damn dirty ape.
ANDY SERKIS: (As Caesar) No.
GREENFIELDBOYCE: It's a shocker. Caesar can speak. He can say no. And all it took was changes in the brain. Tecumseh Fitch thinks that could really be true. He's a cognitive biologist at the University of Vienna. And he says there's long been this assumption that the evolution of speech required massive changes in the vocal tract. But he doesn't buy it.
TECUMSEH FITCH: What you'll find in the textbooks is that monkeys can't talk because they don't have the appropriate vocal tract to do so. That, I think, is a myth.
GREENFIELDBOYCE: He says monkeys normally make all kinds of sounds and lip smacks.
FITCH: So they make grunts, cues. They have these threat vocalizations that are kind of like, heh, where they open their mouth really wide. They would scream if they were in pain.
GREENFIELDBOYCE: He and some colleagues recently used special X-ray equipment to observe a long-tailed macaque named Emiliano. As the machine beeps, you can hear the monkey coo.
(SOUNDBITE OF MONKEY COOING)
GREENFIELDBOYCE: The researchers closely tracked the movements of his lips, tongue and larynx.
FITCH: So what we were interested in is, what are the possible shapes that a monkey vocal tract can take?
GREENFIELDBOYCE: With this information plus computer models, they could figure out what aspects of speech would be physically possible for a monkey. And it turns out monkeys could do a lot. They could produce five vowels. And five vowels is pretty standard for human languages.
FITCH: So what we found is that they can make a very, very clearly - eh, ehh, ah, uh, oh - all of those vowels are within range of a monkey.
GREENFIELDBOYCE: Then the researchers used the computer to simulate what it would sound like if a monkey talked. Let's say a monkey got in to the spirit of the season and said, happy holidays.
COMPUTER GENERATED VOICE #1: Happy holidays.
GREENFIELDBOYCE: Or what if a monkey asked to marry you?
COMPUTER GENERATED VOICE #2: Will you marry me?
GREENFIELDBOYCE: They picked that phrase because it had a lot of vowels. But Fitch says monkeys would be able to make plenty of consonants too. All it would take to talk is the right kind of brain.
FITCH: As soon as you had a brain that was ready to control the vocal tract, the vocal tract of a monkey or any other non-human primate would be perfectly fine for producing lots and lots of words.
GREENFIELDBOYCE: The work appears in the journal Science Advances. And Fitch hopes it kills off the idea that monkeys' vocal anatomy is incapable of speech once and for all. Nell Greenfieldboyce, NPR News.
(SOUNDBITE OF PATRICK DOYLE COMPOSITION, "LOFTY SWING")
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