This is what a macaque monkey would sound like if it suddenly proposed:
Will you marry me?
Uh, yeah, I hate it too. Let's play it again.
Will you marry me?
Now of course, that's not a real monkey; it's a computer simulation that was part of a study on monkey vocal tracts. And what it shows is that monkeys have a strikingly similar vocal structure to humans.
But despite all these similarities, they can't speak.
So here's a question. Compared to monkeys, birds are nothing like us. Yet this bird's talking to me right now.
Birds don't have lips. They don't have teeth. Their nose is totally different from ours. But they do have something we don't.
They actually have a different kind of voice box than we do. That's called a syrinx.
This is Mya Thompson. She studies birds at Cornell University.
They actually have two independent voice boxes.
In birds and in humans, the lower respiratory system is shaped sort of like an upside-down slingshot. The top part is the trachea, or windpipe, the bottom part is the lungs. These two pieces move air in and out.
In humans, the voice box is called the larynx, and it's located above the trachea. It contains vocal folds that vibrate when air flows through to produce sound. And humans primarily shape that sound with their mouths.
But in birds, the voice box is called the syrinx. And it's located at the bottom of the trachea. Instead of just sending air through vocal folds like we do, birds actually control muscles on the walls of the syrinx to shape and produce sound.
Take a look at this cardinal as it sings. You can actually see the noise coming directly from the chest. The bird extends and shortens its neck and opens or closes its beak to refine the noise, but most of the control is actually happening in the syrinx. It's a powerful sound for such a small animal, but that's not even the most impressive part.
Cardinals tend to make these whoop notes, and they go by very, very quickly. They're able to produce more pitches than a piano in less than a tenth of a second. They're actually switching from one side of the syrinx to another seamlessly to make this very, very incredible span of pitches.
The syrinx also lets some birds replicate sounds with astonishing accuracy. For example, BBC Wildlife caught a lyrebird perfectly imitating a camera in the wild.
鳥類也能用鳴管複製聲音，精準度令人咋舌。例如《BBC Wildlife 野生動植物雜誌》就曾在野外捕捉到琴鳥完美模仿相機聲的片段。
And then, of course, some of them imitate us.
Parrots are born communicators. From the start, their brains are wired for speech. So when they're first hatched, they're learning right away. And they're learning from everything around them.
But speaking human is no easy feat. We've got our vowels: a, e, i, o, u.
Our plosives: pocket.
And a variety of consonants that we even struggle to enunciate clearly.
So to pull off such clarity in human speech, parrots really need to show off their ability to manipulate their vocal tract. Plosives, for example, require our lips. To make up for the lack of lips, parrots use something called esophageal speech. It's almost like burping that comes from within the trachea. The force of air replicates the plosive.
As for vowels, where we use our lips, tongue, and jaw, researchers have actually found that parrots move their tongues forward and backwards and adjust their beak opening to alter the sound. And it seems like they are the only birds that are actually using their tongue like humans do to shape the sound that's coming out.
Parrots have a natural desire to communicate. In the wild, they form strong bonds with their flocks. But in captivity...
...the parrot forms a social bond with you and they want to communicate with you, and they have the vocal anatomy to start mimicking you.
When parrots live with us, we're their flock, and they're determined to sing our song.