Instant Genius - How humans learned to speak and why

Episode Date: August 3, 2025

Humans’ unique ability to communicate through complex systems of language is one of the key attributes that separates us from the rest of the animal kingdom. But how did this complex behaviour arise? In her latest book, The Origin of Language – How We Learned to Speak and Why, evolutionary biologist Madeleine Beekman argues that our ability to speak arose due to the need to take care of our children. She tells us how early human’s anatomy changed dramatically when our ancestors came down from the tress and began walking on two legs, how a quirk of genetics allowed humans to develop such large brains that aided the development of language, and why human’s slow development from helpless infants to functioning members of society gave rise to the need for in-group cooperation and complex modes of communication. To get the exclusive gift box from Shokz, order via this link: ⁠⁠https://bit.ly/4kFt10l⁠ Learn more about your ad choices. Visit podcastchoices.com/adchoices

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Every Monday and Friday, you'll hear a world-leading scientist and experts talking about the most fascinating ideas in science and technology today. I'm Jason Goodyear, commissioning editor, the BBC Science Focus. Human's unique ability to communicate through complex systems of language is one of the key attributes that separates us from the rest of the animal kingdom. But how did this complex behaviour arise? In a latest book, The Origin of Language, How We Learned to Speak and Why, evolutionary biologist Madeleine Beekman argues that our ability to speak arose due to the need to take care of our children. She tells us how early humans' anatomy changed dramatically when her ancestors came down from the trees and began walking on two legs, how a quirk of genetics allowed humans to develop such large brains that aided the development of language.

And why humans slow development from helpless infants to functioning members of society gave rise to the need for in-group cooperation and complex modes of communication. So welcome to the podcast. Thanks so much for joining us. Well, thank you so much for asking me. and for reading the book. Oh, you're welcome. So coming on to the book, we're talking about your latest book, The Origin of Language, How We Learned to Speak and Why. So can you first off briefly explain the overriding thesis of the book, and then we'll get into some more details? Well, very briefly, the origin of language lies in the need to look after what I call underbaked babies. The babies are underbaked because their brain is so large that first of, the mum can't extend

the pregnancy because growing a brain is very expensive metabolically. So she will not be able to extend a pregnancy beyond nine months because she won't have enough energy to sustain herself and to grow a baby with a massive brain. But also, a large head in a narrow pelvis doesn't go well at all. And the narrow pelphers is the side effect of us in our evolutionary history, making the decision to no longer swing in trees, but to walk on two legs. So a skeleton changed to adapt to walking on two legs. And one essential adaptation was a narrowing of the pelvis. So these babies need to come out before the heads are too big, to kill mum in pregnancy, or to kill Mum during birth because the head might get stuck.

So what you have is this baby that basically is totally useless and it depends on adults to look after it. And then you get this two-way street. So you have a baby with a very undeveloped brain, but that makes it very neuroplastic. So it's the best learning machine you can imagine. And it uses that capacity to manipulate the people around it to care for it. Because if no one cares for the little baby, the baby dies.

So this is what triggered very precise communication. The baby manipulates the adults around it and others, siblings, etc., to care for it. And the adults manipulate others to ask for help to help them care for the baby. because one parent or even two parents are not enough to look after that baby. So that's basically in a nutshell the thesis of the book. So you sort of kick off the story like you mentioned there that ancestors stopped climbing, stopped running and things and started walking on two feet. So as an evolutionary biologist, that things like, well, you know,

we seem to have lost some important abilities there. So, you know, how did that happen and how did we survive? Well, the interesting thing is I don't think anyone has a good answer for why we came down from the trees. So there's a hypothesis that the landscape changed, that it became drier, but that doesn't explain why chimpanzees stayed in, or the ancestors to chimpanzees stayed in the forest or in the trees, because we split from a common ancestor with chimpanzees about six million years ago. So the ancestor that became chimpanzees, they stayed up in the trees, the ancestor that became humans, they came down from the trees. As is so often in evolutionary history, weird things just happen, and then natural selection either has to find a way to deal with it, then a species survives, or it doesn't, and the species

go extinct. So we humans tend to always want to find an answer for why did something happen, but sometimes things just do. Now your second question, how did we survive? We survived, and now we is our early ancestors, so it's not even our species, but many species before us. They survived by sticking together. So they basically formed probably kin groups or family groups, and they had to because they were surrounded by a lot of large predators. We evolved, humans evolved in Africa, but if you've been to Africa, you know that there's still some pretty dangerous predators around. In those days, there were

many more predators. So if you were a two-legged individual, you can't even run fast enough, you can no longer climb up in trees. You have all these predators around you. So what do you do? You stick together. So that was the way that our early ancestors got around walking on two legs in a very dangerous environment. So you mentioned there our big brains. So we humans, I mean, some of us anyway, like to think we're pretty smart and we do have big brains. So how did our brains get so big?

You know, that must have been such a complicated process. It's actually apparently quite simple. And also I have to say that it's only our species, Homo sapiens, that has an outsized brain. So even our closest relative or ancestors, probably homo-hidal be against us, although no one really knows. Yes, they had a big brain, but they did not have an exceptionally large brain. That exceptionally large brain and the strange form of the head that only happened in our species.

And that was all due to a gene, which used to be a pseudogene, they call it. So a pseudogene is a gene that used to be functioning, and with functioning, I mean. that it coded for a protein. That gene became dysfunctional, and we know that because gorillas and chimpanzees still have the dysfunctional version of that pseudogen, but for some strange reason again, that no one knows,

that gene in our lineage, in our species, got repaired, started to function again, so it's again started to code for proteins, and proteins do so. something, often do something useful. Not only did it get repaired, it also duplicated itself. And with every duplication, it had an effect on the growth of the brain, to such an extent that with every duplication, more neurons were produced. Now, the neurons were produced, actually, let me use the metaphor of a slowly inflating balloon as an example. So with the duplication,

of the gene, more neurons were produced so that the developing brain basically started to get bigger in the same way as you would slowly inflate a balloon. And again, so as I said earlier, this was just a fluke of nature. No one has an explanation. And why did we get away with it in a sense and why didn't it make us go extinct? It's because our heads to simply adapt it, because the skull is a very malleable structure. It's composed of all different bits and pieces that sort of fit together, hang together. And this skull was basically able to just work around with this immense grey matter, this growing brain, to produce the very strangely formed skull that we have. So we have a very bulbous head. If you look at someone who doesn't have any hair, and you look at our

profile. You see that they at the back have this weird, weird thing. Well, actually, just look at babies' heads. Babies have the strangest heads ever. They're tiny little things, but their head is just enormous, and that's because they have to fit in all that grey matter. So, again, it's a fluke of nature, but it's served us well so far. Yeah, so I think this is really interesting. So am I right in saying this? So let's take one of my favourite animals, a giraffe. So as soon as the giraffe's born, 13 minutes to an hour, they're up and running around. Whereas compared to a human baby, that takes an awful long time. So is this sort of maturation process keyed in with our big brains?

Yes, I guess it's a trade-off. So I have a granddaughter. She is now three and a half months old, and she finally figured out her to turn herself over. So she can turn herself from her back onto her belly, but once she's on her belly, she doesn't know what to do anymore, so then she gets into panic, and then her parents have to roll her back. So if you contrast that to what you say, a giraffe, that despite falling, what is it, two meters or something when it's born, it falls on its head. It's probably concocted for a little while, but then it picks itself up and starts walking on these funny little legs,

were actually quite tall legs, and then in no time it can run with his mum. But of course the giraffe has to run away with its mum because otherwise it would be a snack for one of the big predators. So we got stuck in this other way of looking after young, or the babies basically got stuck in, having to live in family groups with other individuals looking after them because they're so pathetic, because their brain is done. Don't quote me on the exact percentage, but when a human baby is born, I think the brain is only about 40%, so that's 4.0% of its adult size.

So that means it needs to grow tremendously. Most of the energy that goes into a baby goes straight to the brain because it has to use a lot of energy to keep that brain, not just running, but also to grow it and to develop. bit further. So you basically can't have your cake and eat at all. You either are a giraffe or a giraffe-like creature. You invest in becoming agile really quickly so you can run away from the predators or you become a pathetic little human that really has to manipulate its environment so that it doesn't die from starvation or from anything else. Yeah, so coming on from that, so let's have a look at how humans we are young or, you know, ancestral humans, etc. So we're essentially, correct me if I'm wrong, pair bonded mammals.

So what role is that played in this whole situation? We are pair bonded mammals because one parent can't look after a baby. So again, just go back an evolutionary time before we even had a huge brain, so before our species. Let's take Lucy as an example. Most people probably heard of Lucy made famous because of the Beatles song Lucy in the sky were diamonds, which was popular at the time when her skeleton was found.

But Lucy was a member of the species Australopithecus apharencis. So a primitive human, but a human who walked on two legs, probably no longer had hair, probably had a pelfus that was quite narrow, not as narrow as our pelfast, and her babies didn't have a big brain, but still, again, because she was walking on two legs, the skeleton had to change, so the pelfast tilted slightly, and that changed the orientation of the birth canal,

which means that Lucy's babies, and this is contested because not everyone agrees, but I think it's a reasonable assumption that Lucy's babies had to make an internal turn before they could basically be born, which means that when they were born, they were facing down. So, mum, if she would be looking as the baby comes out, she would be looking at the back of her head. In all other apes and monkeys, babies are born facing mum, so that means that mum can help the baby out. She can put her hand under the back of the head of the baby and, you know, softly try and ease it out. Lucy probably couldn't do that anymore. So that means that she probably could not give birth by herself. So she needed someone else to be there. The other downside of walking on two legs is if you have

babies, what are you going to do with the baby? You can't throw it on the back of your back because the baby can't hold on because you're now upright. So many toddlers of chimpanzees and gorillas, etc., they start on the mum's belly, but mum has to hold the little baby on the belly, but once they're a little bit older, they ride on the back of the mum, which is easy because mum walks on four legs. But Lucy no longer walked on four legs. She walked on two legs, which meant baby can't hold on to mum. So what does mum have to do? She has to hold baby. Now, if you hold a baby, there's not a lot else you can do. So this means that the father became important to help the mum, not just help mum look after the baby, but also to make sure that there was enough food for

mum and the baby and for the father. So this is where the pair bonds probably started. But as I said earlier, because once our ancestors left the trees and started walking on two legs, they had to stay together as a group, because that gave protection against all the scary predators. You said this place was steps from the water. We just haven't found the steps yet. How much did we save? Enough.

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and unforgettable listening experiences at home. Try it for yourself at a focal powered by name boutique. Visit focal powered by name.com for more information. So let's have a look at sort of the language section of this then. So something that I think is interesting. I love dogs, for example. I used to have a dog and he used to sort of be able to communicate. communicate with me. You know, if he wanted to go to the toilet, he'd come and go,

woo. So I'd say, okay, pal, I know you need to want to go into the garden. And I'd also say he'd learn things as well, the names of his toys. I'd say, you know, would you like to go for a walk or fetch your lead? He'd understand all of those things. So of course, that's very basic. But, you know, that must have been a similar way to how it started with our ancestors. Definitely, because all social species have to have some form of communication. Most of my academic career are worked on ants and bees, so social insects, and they all have their own form of communication. Why?

Because you can't organise a society if you don't have any form of communication. Now, dogs are very social animals that just made this mistake somewhere forced by humans to form social bonds not with other dogs. Of course they do that too, but mainly with humans. And they depend on humans because a dog can't open a tin of dog food. So it has to be able to communicate with humans, but because they're a social species, they already had this empathy,

being able to understand what the other individual is feeling, to some extent, body language, being able to respond to body language, because I'm sure the dog would have realized when you were really sad or really happy or very angry, particularly if you were angry with the dog. All these things, emotions, so body language, empathy, sort of mind reading, because empathy is a form of mind reading, but all basic, the basic forms of communication. What we have done is we just level it up by all these, all these forms.

flukes of nature being able to form these very precise words that we have given meaning, and we've given them such a meaning that we can basically use words in an infinite number of ways to say whatever we want. We can talk about things that don't exist. We can make things up that make people believe in. We can talk about the future. We can talk about the past, etc. And that's because we have built on empathy, body language, mind reading, trust. Trust is really important in communication because otherwise communication can never be honest. If you cannot trust the person you're communicating with, then communication breaks down, as we've probably all realized, that if the other person doesn't really know what you're talking about, then you're not going

to get anywhere. All these things were based. the basic prerequisites for something more sophisticated as our language to be able to evolve. So how about our vocalizations then? It's incredibly complicated, isn't it? And you talk about something called phonemes. So could you explain that for us? So phonemes are the smallest sounds you can make. So I think the examples I gave us, for example, the th, or the t, or the k.

So there is a good example, I think it's a phoneme. So these are, you can split language in little sound bites if you wish, and then the smaller soundbite is a phoneme. Now, certain phonemes, like you, require enormous control over your tongue and over your lips, and that is what makes human special that we have that control. So if you've ever had anesthetic at the dentist, you know that your lips don't really want to do it, you want them to do anymore, your tongue may not necessarily want to do it, you want it to do, and your speech becomes very, very blurred.

And that shows you how important it is to have this very precise control of all these tiny little muscles, as I said in your tongue, your lips, but also your breathing, because your breathing is extremely important for precise language. Why can we do all these things? We can do all these things because of the way our throat has developed. So with our skull adapting to make space for that expending brain, which started expending because of this weird genetic fluke, our throat became longer,

and our tongue was pulled. down, back down into our throat. So most of our tongue actually sits in our throat, sort of of halfway in our throat. And that, for some reason, gives us more control over the way we move our tongue. It's actually quite a funny, a fun game to play. If you just think about sounds in your head. Without saying them, and then just by thinking them, you know what you need to do

with your tongue and your lip. Where do you put your tongue? Do you put it in the front of your mouth against your teeth or at the back, and what do you do with your lips? So you can feel how you make those phonemes, and no one or nothing that doesn't have the control that we have will ever be able to make those sounds.

So having said that, you mentioned there Lucy earlier, one of the sort of early human ancestors. What do we know about their sort of anatomy of vocalization? That's a very good question. And it's very problematic because the larynx, which is the essential part, the voice box, is soft tissue and it doesn't fossilize. People can always criticize my idea by saying, you don't know who spoke or who didn't speak because you can't prove it. And that's, of course, a problem in general, I think, when you look at evolutionary history of a particular species and you want to, you know, try and go back a few million years, you can never prove it. There's no time machine, I can't go back and ask Lucy, excuse me, can you speak?

But I'm pretty convinced that we, Homo sapiens, are the only species that is able to have this very precise communication. The reason being, it's as I mentioned earlier, it requires a particular morphology. So the throat needs to be long enough. The larynx needs to be positioned in the right place. And Neanderthals, their necks were too short. Another thing that I should mention is we have a very flat face. It's not because we always kept falling on our face when we started running, but it's an adaptation to running actually,

because if you have a protruding snout, your head is basically sort of pushed forward. And that doesn't quite work if you want to be able to walk fast on two legs. So a flat face is an adaptation to fast walking or fast running. But it's also a side effect of the skull changing its shape again to fit that large brain in. Now, if you ever seen reconstructions of the under tiles, you know that they had a still sort of a bit of a snap. They did not have this bulbous head that we have, and their necks are much, much shorter. So therefore, people have argued that the necks were so short that they would not have been able to, that they basically did not have the morphology that allowed them precise speech,

which is not the same as saying that they had no clue. communication at all, because as I said earlier, all social creatures need some form of communication. What I'm arguing is that their communication was nothing compared to what we have. So once sort of our ancestors have developed some, let's say, rudimentary form of communication, then we're able to cooperate more. So how does that drive our evolution? More cooperation has a lot of effects on species because of the feedback you get. So the more social interactions you have, the more your brain is stimulated, so the more precise or more elaborate your social relationships can be, which then feeds back again on

your intelligence, if you want. But of course, what really sped up our species evolution is cultural evolution, the ability to teach more directly, to learn from others, to trade with others. All these things became possible with language, and that really has sped up our evolution. Because if you think about it, our species probably made its first appearance in Africa about 300,000 years ago. That is nothing in evolutionary time. And now here we are.

You know, we're shooting rockets. We're aiming for Mars. First moon was quite an achievement. Now we're aiming for Mars. That in 300,000 years. Cave men 300,000 years ago, and now we have plans to colonize Mars. This is not just normal evolution. This is cultural evolution and culturally evolution driven by language.

So if we're talking about language, I think I have to ask about a lot of people, want to know this about acquisition of language. So, like, as a person example, when I was in my 20s, I lived in Japan for several years. I studied the language really diligently. And it was kind of a source of amusement and frustration to me that five-year-olds were still much better speaking it, even though we'd spent the same time learning it. So what can we say about that? Yes, it's not fair, is it? No. I'm not trying to learn Spanish, and I can assure you it's much harder than I ever had to spend time learning Dutch when I was a little child.

So for some people, a language eccresition is such a miracle that they almost see it as a miracle. So then, plop, something magic happened, and babies can learn toddlers can just learn language. So they would even argue that language cannot have evolved by natural means, so it cannot have evolved by natural selection. I don't agree. Language is special because we are the only ones who have this strange form of communication. But I would like to see language almost as a virus, and that's not my original thought.

So the thought is, and I think Terence Deacon came up for that, idea for the first time. So he tried to explain why is it much easier for young children to learn language than it is for older people? The explanation of people have always given is that there's some sort of particular language plasticity in a child's brain that at some stage basically shuts off and then it becomes much harder to learn a language. He turns it around. So he says, language relies on humans, just like a virus relies on a host. If there's no host, then the virus will go extinct. If there are no humans, then the language will go extinct. Language has to get itself into a baby brain, to be able to spread from brain to brain,

just like a virus needs a host to go from host to host. So languages, the structure of languages are perfectly adapted to be able to be picked up quickly by a baby brain. And I think that's just a wonderful idea because it explains why children are just magical at languages. So they invent their own language. If you put a group of kids together and they don't have a common language, it doesn't matter. They figure it out.

That's how Pigeon languages, or linguists do not refer to pigeon as a language, but that's how pigeon originates. It's just a language, a common language that's a combination of all the languages, all the different people that try to communicate with each other, use to communicate. Kids do it all the time. They're just sponges, and they're sponges because that is what the language wants, air quotes.

Of course, language doesn't want anything, just want to be spread from brain to brain. And of course it gets used language to manipulate the world around them. So we've covered an awful lot there. So I've got obviously we're speaking in English, which is my native language, not yours. But looking into the future, do you think language will ever develop, evolve into a global lingua franca? Well, haven't people tried with Esperanto? They try to make Esperanto a universal language.

And it's funny because I once met an Esperanto speaker. And that's what I said to him. I said, oh, I've never met an Esperanto speaker, and he said, you'll probably never meet one again. So that already indicates that that idea never took off. So I don't know, I don't think so. And also I hope it won't because wouldn't life just be a bit more boring? Yes, it will be easier because everyone speaks the same language,

but at the same time, it'll be boring. So let's not. Thank you for listening to this episode of Instant Genius, brought to you from the team behind BBC Science Focus. That was Madeleine Beekman. To discover more about the topics we've just discussed, check out her book, The Origin of Language, how we learn to speak and why. If you liked what you just heard, then please do consider subscribing to Instant Genius on your preferred podcast platform. If you'd like to see our guests and hosts in person, then please also check out our YouTube channel, at Science Focus. The current issue of BBC Science Focus magazine is out now.

Pick up a copy wherever you buy your favourite magazines or download us on your app store of choice. You can also find us on Apple News or online at sciencefocus.com. This podcast is sponsored by Name, Audio and Focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name audio believes you can have digital precision with analogue warmth. Alongside French acoustic specialist vocal,

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