For a while now, I have been wondering how we would communicate with aliens[^1] if we ever got to talk to them. Whether this question is in any way relevant or useful depends on whether or not you believe that extraterrestrial intelligence exists, and is close enough for us to come into contact with them, either directly, or by sending messages to each other. Unless I’m mistaken, nobody knows for sure. Personally, I’m pretty certain that there is intelligent life out there somewhere, because space is huge, there just has to be someone other than us living here, right? However, because of the universe’s aforementioned size, travelling, or even sending messages, between different star systems takes a very, very long time. That means that for us to communicate with aliens, not only would they have to exist, they would also have to live fairly close to us. And I’m much more skeptical of that second condition being true. I could be wrong, but I don’t think we would’ve missed a whole other civilization on a planet close enough to ours so as to enable communication. Nonetheless, I remain fascinated by this question, even if it is only theoretical, because I think it’s a very interesting topic to think about.

I believe my interest in talking to aliens begun after I watched the movie Arrival (2016), that tells the story of a linguist who tries to communicate with an extraterrestrial species that has arrived on Earth. Initially, I assumed the depiction of the way in which the protagonist tries to talk to the newcomers was pretty unrealistic, but I started thinking about what we would actually do in such a situation. Well, as it turns out, Arrival was pretty accurate! Betty Birner, a linguistics professor, was interviewed about the accuracy of Arrival, and said that she would approach the task set before the protagonist in a very similar way. She would start by sharing words for different concepts that she could easily show, for example pointing at herself and saying/writing “human”, and hoping her interlocutors would do the same. She would then try to deduce some basic characteristics of the alien language, and sort of go from there, using the basic terms to define further, more complicated terms, and, hopefully, eventually talk.

Unfortunately, I was unable to find many resources about how we would talk with an alien standing right before us, other than that appraisal of Arrival’s accuracy, presumably because it is such an unlikely scenario than nobody is even considering it. However, people are, and have been, thinking about communicating with extraterrestrial intelligence over long distances via various methods.

It seems like historically, especially in the 19th and 20th centuries, people were pretty much certain extraterrestrial life not only existed, but shared a star with us. In 1820, a proposal, usually (though not all sources are clear on this) attributed to mathematician Karl Gauss, to grow a diagram of a right triangle out of wheat in Siberia was put forth. The triangle was meant to let Martians (inhabitants of Mars) know that life on Earth existed, and was intelligent enough to understand mathematics well enough to know that there was something significant about a right triangle. How Martians were supposed to see the triangle from their planet, or why Gauss seemed so sure that there was anyone on Mars to see the triangle, I do not know. Some other 19th century life-on-Mars believer wanted to build a massive mirror which would be used to focus sunlight into a beam and use it to burn messages in Mars’s surface. Presumably to motivate similar attempts at contacting civilizations living beyond Earth, a prize of 100,000 francs was offered by a Parisian academy to whomever would be the first to talk to aliens. However, contacting Martians was excluded from the prize, because it was deemed too easy. Obviously.

Nowadays, people are much more skeptical about aliens’ existence, and we’re almost certain that there’s no one in the Solar System. Nonetheless, we keep trying. Most of our efforts are spent on listening for messages that extraterrestrial civilizations might have purposefully, or accidentally, sent our way. This effort is called search for extraterrestrial intelligence, or SETI for short. So far, the most promising signal we overheard was one called the “Wow! signal”, but, due to its lack of repetition, it has not been confirmed as a sign of alien intelligence. Humanity’s efforts are not limited to just listening for alien signals, we also send plenty of our own signals and messages, in the hopes of them being received by some extraterrestrial civilization.

NASA’s Pioneer 10 and 11 are spacecraft whose trajectory took them beyond the Solar System. For this reason, before their launch, Carl Sagan, a notable figure in the field of CETI (Communication with extraterrestrial intelligence), designed a plaque that ended up being included on both Pioneers. The plaque, meant to tell potential finders, where, when, and by whom the spacecraft were sent out to space, includes crude drawings of two humans with their heights inscribed next to them, a diagram showing the planets in the Solar System, and a depiction of the Sun along with distances between it and nearby pulsars[^2], along with their respective periods (the time it takes for a pulsar to complete one full rotation)[^3]. As far as we know, ours is the only star system in the Milky Way that fits the given description, and, because the periods of pulsars change over time, the periods included on the plaque can be used to determine when it was created. To communicate the aforementioned distances and amounts of time, we needed units that aliens could understand. For this, properties of hydrogen atoms were used. Because hydrogen is the most common element in the universe, the creators of the plaque hoped that the plaque’s finders would have studies it and gotten to know its properties.

The Pioneer Plaque was, however, the only physical message sent to space that I was able to find mention of - most of the signals we send to space are in the form of electromagnetic waves. In these signals, we obviously can’t use any language spoken on Earth, because no alien civilization would be able to understand it (unless, by some insanely unlikely coincidence, some aliens developed a language exactly like one of ours). Instead, we usually rely on mathematics and logic to establish some shared “language”. According to some, mathematics (and logic) is not something humanity created, but something we discovered, studied, and attempted to described using symbols and nomenclature we devised. If this is true, there’s a high chance that any intelligent society would also have discovered math (and logic), and would be able to understand some concepts, such as prime numbers, or right triangles (the subject of the 1820 proposal I mentioned above).

Astrolinguistics, a book by Alexander Ollongren, gives a detailed explanation of a language called LINCOS, designed for use in communication with aliens. The book is very long, very technical, and I had neither the time nor the intelligence required to fully read and understand it. However, from my attempt at reading the introduction, I did manage to figure out that LINCOS is based on logic. Rules of logic, just like mathematics, are also something which we think might be common to all potential intelligent being. LINCOS uses it to sort of explain itself as it goes, and then proceeding to use the established language rules to actually communicate something.

As you might have noticed, all of our attempts hinge on the assumption that we have something in common with aliens. We assume they can understand mathematics, or that they know logic, or that they have studied hydrogen. We assume they think in similar ways to us, that they listen for radio waves coming from space, that they would try and succeed at decoding these waves. But really, we have no idea whether any of these assumptions are true. To make them is only natural - David Hume said that we have a tendency to imagine things as similar to us, and it’s hard to be surprised. We are ultimately by our perspective, and it’s extremely difficult, if not impossible, to imagine just how different extraterrestrial intelligence is from us. For all we know, they could be so incomprehensibly different from us that they think, act, look and communicate in ways unfathomably distinct from us. We don’t even know to what extent aliens could be different, let alone what those differences are.

This might seem like a disappointing conclusion, but I think it’s beautiful. I came away from this little investigation of mine with the realization that humans are doing their darnedest to find out if there is someone out there, and to hopefully talk to them. Personally, I think that someone is living out there. Maybe they’re immensely different from us, maybe they don’t have a language because they’re a hive mind, maybe they don’t have a mind at all. Or maybe they are just like us, struggling with the same problems, finding joy in the same things, just on a different planet, speaking a slightly different language, somewhere far, far, away.

We’ll probably never know.

References

[1] ‘Alien language’, Wikipedia. June 06, 2025. [Online]. Available: https://en.wikipedia.org/w/index.php?title=Alien_language&oldid=1294241321
[2] ‘Astrolinguistics’, Wikipedia. May 10, 2025. [Online]. Available: https://en.wikipedia.org/w/index.php?title=Astrolinguistics&oldid=1289672003
[3] A. Ollongren, Astrolinguistics: Design of a Linguistic System for Interstellar Communication Based on Logic. in SpringerLink Bücher. New York, NY: Springer, 2013. doi: 10.1007/978-1-4614-5468-7.
[4] ‘Communication with extraterrestrial intelligence’, Wikipedia. Sept. 03, 2025. [Online]. Available: https://en.wikipedia.org/w/index.php?title=Communication_with_extraterrestrial_intelligence&oldid=1309388385
[5] K. Howells, ‘How do humans try to communicate with aliens?’, The Planetary Society. Accessed: Sept. 21, 2025. [Online]. Available: https://www.planetary.org/articles/how-do-humans-try-to-communicate-with-aliens
[6] M. Martinelli, ‘How Realistic Is the Way Amy Adams’ Character Hacks the Alien Language In Arrival? We Asked a Linguist.’, Slate, Nov. 22, 2016. Accessed: Oct. 02, 2025. [Online]. Available: https://slate.com/culture/2016/11/a-linguist-on-arrival-s-alien-language.html
[7] ‘Is it time to chart a new path for xenolinguistics through sci-fi? | Aeon Essays’, Aeon. Accessed: Sept. 25, 2025. [Online]. Available: https://aeon.co/essays/is-it-time-to-chart-a-new-path-for-xenolinguistics-through-sci-fi
[8] ‘Onward to Mars - TIME’. Accessed: Sept. 24, 2025. [Online]. Available: https://web.archive.org/web/20081203211455/http://www.time.com/time/magazine/article/0,9171,967915-4,00.html
[9] ‘Pioneer 11’. Accessed: Sept. 27, 2025. [Online]. Available: https://science.nasa.gov/mission/pioneer-11/
[10] ‘The Pioneer Plaque: Science as a Universal Language’, The Planetary Society. Accessed: Sept. 27, 2025. [Online]. Available: https://www.planetary.org/articles/0120-the-pioneer-plaque-science-as-a-universal-language
[11] W. Sullivan, ‘The Universe Is Not Oues Alone; From the edge of the galaxy’, The New York Times, Sept. 29, 1968. Accessed: Sept. 24, 2025. [Online]. Available: https://www.nytimes.com/1968/09/29/archives/the-universe-is-not-oues-alone-from-the-edge-of-the-galaxy.html

Footnotes

¹

When I say alien (or aliens) in this post, I mean an intelligent being of extraterrestrial origin (not from Earth). Alien is obviously a much less professional term, but it’s also way more fun.

²

Pulsars are special stars that spin. Read more on Wikipedia if you’re interested.

³

If you have any thoughts or comments please feel free to contact me.