With the arrival of “Arrival” at a cinema near you, a lot of people have been talking about talking with aliens. And while the film already makes it look pretty complicated, it is quite likely far simpler than what the reality of communicating with extraterrestrial life-forms would be like.

To use an understated example, the 26 letters of the English alphabet are used by many languages, which use the same letters but with different sounds or the same words with different meanings. So if you put a message with the secret of life, the universe and everything in a bottle and cast it adrift, and someone picked it up on the other end of the world without not just not knowing the English language or the alphabet or even that such a language existed and didn’t have anyone to learn from either, the bottle carrying the message would perhaps be of a lot more interest than the message itself.

Douglas Vakoch, president of the newly formed Messaging Extraterrestrial Intelligence (METI) International who formerly worked at Search for Extraterrestrial Intelligence (SETI), referred to the protagonist from “Arrival” in an interview with Motherboard: “I am so envious of Louise Banks because she gets to have a face to face with ET. But in the scenarios that SETI and METI folks deal with there’s no possibility of that. Our idea of a snappy exchange with extraterrestrials is a decade — and that only works if the nearest star is populated.”

For one, unlike in the movie, we can’t assume that aliens will land on Earth and give us the chance to teach them the symbols that humans put together in pre-agreed combinations to convey pre-decided meanings. If we didn’t have physical contact with them, we would have to transmit messages over very long interstellar distances that would take, given current technology, years to come and go. And to be understood by an alien intelligent species, they would need to be in a package entirely self-referential.

Such a package would contain the message as well as instruction needed to understand it, and the instructions would have to be in a language that the aliens would understand without needing another manual to explain it (because such a list of manuals could go on ad infinitum).

“We're looking for a cosmic Rosetta stone,” Vakoch told Motherboard. “But the question is: What do us and the extraterrestrials both have in common?”

There are proposals of using mathematics and science as languages, based on the assumption that an alien species that is intelligent would have to use the same scientific and mathematical principles to create technology that would be capable of receiving and sending messages. But even those are not fool-proof solutions.

Sheri Wells-Jensen, an associate professor of linguists at Bowling Green State University, Ohio, told Inverse: “We’re only beginning to understand that the way we think and communicate and what we build is determined by the way our bodies are shaped and our sensory apparatus. … What if you had a race of aliens that couldn’t see? In what ways would that change the way they built their civilization and how they understand their world? We have some data to suggest that the way we are physically built might influence the way our language is structured. It’s because we walk erect, our top appendages are free, and we have to use our hands to do things.”

So what can we do then? According to Vakoch, believe in the power of numbers. Not mathematics, but sheer numbers to increase your odds.

As he told IBTimes UK in February this year: “I sure hope they're going to beam us a load of prime numbers and we can say 'a-ha, we know maths'. But maybe that's not it. I think a more productive strategy is to think about the various divergent forms of messages we might transmit.”