Some monkeys are actually physically capable of producing human speech. But their brains just aren’t wired to do so, according to research published in Science Advances.
Researchers recorded X-ray of a long-tailed macaque’s vocal and facial movements as he made different sounds, like coos, grunts, yawns and lip smacks. Then, they used a computer model to simulate possible sounds based on the vocal configurations they captured.
They found that macaques could theoretically produce many the sounds needed for “clearly intelligible” human speech — including all five vowel sounds.
So why haven’t they actually develop the capacity to speak?
Well, the researchers say monkey’s brains aren’t “speech ready.” They lack the ability to perform the complex vocal learning and speech control that humans have — which is why scientists have never been able to successfully train primates to speak.
But even if they could talk, they probably wouldn’t sound exactly like us. The computer’s simulation of a macaque saying “Will you marry me?” sounds incredibly creepy. (Listen below.)
Up until now, scientists have debated whether it was anatomical or cognitive differences that make humans capable of speaking and not animals.
“Even if this finding only applies to macaque monkeys, it would still debunk the idea that it’s the anatomy that limits speech in nonhumans,” said Asif Ghazanfar, one of the study’s authors, in a press release by Princeton University.
“Now, the interesting question is, what is it in the human brain that makes it special?”