“We know where to look. We know how to look.” That’s what then Nasa’s chief scientist Ellen Stofan said in 2015 when she predicted we might find alien life within the following 10 years. Today, only two years from the end of that date range, researchers believe they may be tantalisingly close to finding evidence that extraterrestrial life might well exist on far off planets. But while there is no definitive proof as yet, some scientists believe it is something we should be preparing for.

So, what if we do discover life on another planet? And if it turns out to be intelligent, how might we communicate with our cosmic neighbours? Scientists are already beginning to ask what alien language might be like and if our species could ever hope to understand each other.

Humans have a long history of bridging seemingly impossible language barriers. Researchers who decipher ancient scripts and languages use shared human habits as a reference point. For example, the way we might circle something important in writing helped scholars unlock the Rosetta Stone, a decree that dates to 196BC that provided a clue to reading ancient Egyptian hieroglyphs. Body language is also an important tool – when the Spanish conquistadors arrived in the Americas, for example, they used hand signs and gestures to communicate with the indigenous people they met. The tragic, bloody outcome of those encounters, perhaps shouldn’t serve as an example of how this can be done successfully.

Humans, however, are a species that has evolved to communicate with one another. Extraterrestrial beings may think and behave in a completely different way to us. Their social structure – if they have one – could be totally unrecognisable or even unfathomable. So, how could we guess what they might be trying to say? 

If you were to listen to Earth from outer space, you’d hear around 7,100 human languages. But our planet is inhabited by creatures other than just humans. Could the ways animals communicate with one another teach us anything about extraterrestrial communication?

Arik Kershenbaum, a behavioural ecologist at the University of Cambridge, UK, believes evolutionary challenges are truly universal, and that the evolutionary forces that shape life on Earth will produce many similar features in extraterrestrial life. If he’s correct, it would mean life – and language – throughout the cosmos may share certain features.

Life achieves complexity, over many millennia, by retaining favourable changes and losing unfavourable ones – otherwise known as natural selection. In evolutionary convergence, unrelated lineages of organisms evolve similar features in response to similar environmental challenges.

Take travel – the laws of physics and biomechanics constrain the number of different ways it is possible for animals to move about. This is why the wings of birds work in very much the same way as the wings of bats, even though their last common ancestor was a small wingless lizard-like creature that lived over 300 million years ago.

You might also like:

• The weird aliens of the 19th Century
• Why aliens might already know human’s exist
• The languages that make maths easier

Why would such constraints be different anywhere in the universe? Everything everywhere – communication included – is subject to the laws of physics (as far as we know). From the gestures of apes and the whistles of dolphins, to the swirling patterns of colours on the skin of a cuttlefish, any one of these, argues Kershenbaum, could be the basis of language on an alien planet.

Animal communication can only tell us so much though, according to Ian Roberts, a professor of linguistics who is also at the University of Cambridge. “We are the only species that have language in the sense of an open-ended system which can be used to express anything you want to express,” he says.

Roberts recently co-authored a book, Xenolinguistics – alongside Kershenbaum, Avram Noam Chomsky and other leading biologists, anthropologists and linguists – to explore what non-human, non-Earthbound language might look like.

A theoretical linguist, Chomsky defined language as a system of communication that is infinitely adaptable, designed to serve human interests and to solve human problems – one that’s flexible enough to communicate a very large number of concepts.

“It may well be that there’s some kind of bacterial life on Mars or on the moons of Jupiter – but these would be very simple organisms,” says Roberts. “What I’m interested in is the nature of intelligent organisms. So, you have to decide, what’s the criterion for intelligence?”

The answer to that, says Roberts, is technology – a technological civilisation, comparable to ours, with the ability to get off their planet. 

“Wouldn’t they be sitting there, on their planet, wondering who else is out there? Wondering whether we exist?” he says. “Let’s say a species is intelligent enough to want to build a spaceship, or a radio telescope — something complicated. You’d need to know a lot about physics and mathematics. You’d have to have the ability to develop scientific theories and to collaborate. You would have to be able to communicate a very large number of ideas to a lot of other individuals. The fact is, [other] animals have not developed technology.”

Without language, says Roberts, a technological civilisation would be inconceivable. 

How alien could alien language be?

In 2022, Roberts helped to establish The Cambridge Institute of Exo-Language (CIEL), with the goal of considering how we might communicate with intelligent exo-beings, and how different alien language and intelligence could be from our own.

“My personal opinion is that, at its core, the language would have to be quite similar to ours in the sense that its formal mathematical nature would be similar to human language,” says Roberts. “But at the same time they wouldn’t necessarily have anything like speech.”

Even human language, explains Roberts, comprises much more than just speech – we communicate through writing, body movements, drumming, whistles and more. “What’s really remarkable about human language is that whatever form it’s carried in, it has fundamentally the same properties,” he says. “It’s interesting to question: we have a good idea what human grammars look like, so what might alien grammars look like?”

Intelligent exo-beings, says Roberts, might externalise their language in ways that we can’t yet imagine, “through pheromones, magnetic fields – who knows what? But if we could decode that language, we would find it to be very similar to human language.”

Even if we did receive a signal from outer space, whether would we recognise it as a message in the first place is debatable.

“For a time people thought there would be certain regularities in a signal that would make clear it wasn’t natural,” says Roberts. “But certain celestial bodies do emit very regular signals, such as quasars. We would need evidence that there was some kind of an intention behind the signal.”

The key, says Roberts, is to look at the things we have in common. Roberts sits on the Advisory Council of Messaging Extraterrestrial Intelligence (Meti), an organisation founded in 2015 to send messages from Earth to outer space in the hope of receiving a reply.

Meti’s messages are designed to demonstrate humanity’s intelligence, containing information on things that extraterrestrial beings with any similar level of intelligence would understand. These include the periodic table of elements, the chemical building blocks of the Universe – something scientists on another planet would likely know about. Other messages feature mathematics that describe shapes found in nature, such as the spiral of the nautilus shell; the value of Pi to a certain number of digits; the chemical formula for water; information about the physics of hydrogen; and so on. 

The idea is to convey “very basic scientific information encoded in a particular way, which would make it clear to any aliens who managed to decode it that we had scientific knowledge”, says Roberts.

So, if intelligent exo-beings were to send out messages, might they do the same? And would we recognise it as a genuine signal?

“My gut feeling is that we would be able to tell one way or another. Because, just as when we send signals, they would want to send us something that was recognisable too,” says Roberts.

But could we decode alien language? Could we have a conversation? That, says Roberts, we won’t know until we make contact.

—

If you liked this story, sign up for The Essential List newsletter – a handpicked selection of features, videos and can’t-miss news delivered to your inbox every Friday.

Join one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram.