(Hypothetically.) If someone/something is telepathic, do they have to speak the same language as a person they would communicate with?

I believe telepathic communication is concept based, not actual word for word.

I’m going with no.

I think that if an alien is communicating with a human telepathically, it necessitates translation.
It starts with basic biology. While the aliens may telepathically communicate amongst each other without trouble, you can not just inject these thoughts into an alien brain that operates on very different principles. You would need to first understand how the human brain processes signals, what parts of the brain handle sensory input, and then figure out a way to manipulate the brain to interpret whatever energy fields you project into them as, say, auditory signals. You would also have to somehow prevent your telepathic thought to completely override the existing thought, so you actually end up with the situation of your target “hearing” your thought, and not the target’s thought _becoming_your thoughts.

And then you have to consider that, even if you transmit “concepts”, that they might mean very different things to them, if they have any meaning at all.
Take the example “We mean you no harm.”
“We”. Do they mean the individual speaking to you? The group on the ship? The entire civilisation? Are they a hivemind, without the concept of an individual? What does “We” even mean in this case?
“You”. Do they mean just you, personally? Humanity in general? Do they just mean your consciousness, and they’ll mutilate your body at will, since your bodily integrity is meaningless to them? And if they are a hive mind, with no concept of individuality, are they even talking to you, and not just use you as a supposed conduit to the rest of humanity? Maybe they see humanity as a whole organism, and you are just an ear?
“Harm” is equally undefined. Again, if they are only concerned about your consciousness, cutting off parts of your body might not be seen as harm. Maybe “harm” only means permanent damage to them, so torture is fine. And if they see Humanity as an organism, and you just as a minor component, even killing you might not qualify as “harm”, just like trimming a finger nail, or cutting off hair does not count as an injury.

Great question @MrGrimm888 I dont know. Some body language is universal. Like the pee pee dance, and cringing when someone is kicked in the nuts.

It really depends on what you’re talking about.

I know of fictional telepathy that sends words. That does require a shared language to communicate well, although a recipient could remember the sounds and then find out what they mean later from people or books.

And, as in actual real-world dreams, meaning often uses the current reference set of the brain receiving the message. That is, we usually dream in symbols we already have in our brains, and/or our brains find symbols we have to represent what a dream’s message is, though our sleeping brains are often organized differently from our waking mind, such that we have dreams that make sense to our sleeping mind, but later our making mind has a hard time remembering the details, or when we do remember, has trouble making sense of what we do remember, or even remember how it seemed to make sense when asleep.

There are also fictional telepathic methods that talk about sharing consciousness, such that, at least temporarily, people know, think, and/or feel what the other person does (or what they send them), and this does not require language – it just sends feelings, impressions, or understanding. This might not require language. Or a person with this ability might learn to send ideas in a way that doesn’t require the recipient to use language to get the message.

Now, there are some stubborn people who will insist that meaning and ideas absolutely require language, but I would say that animals and insects routinely demonstrate this isn’t the case.

Then there’s also communication that people and animals do with body language, grunts, expressions, that clearly doesn’t require language, too. This is possible even without telepathy.

And there’s also communication possible, whether it’s telepathy or not, where you do what one communication course I took called “disappearing the space” between two people, where you just let go of your thoughts and separateness, and can just kind of have a shared experience where you’re not really sure who’s doing what, but you’re both on the same page. That’s not about language.

Language does generally require more precise communication, and confirmation, of details, though. I don’t know how to communicate “17.3 cm” (for example) using wordless rapport. (At least, not efficiently or without a ruler.)

^Well. “Body language,” would likely be different with lifeforms from a different planet.

It would also require eyes/vision, similar to our own.

”^Well. “Body language,” would likely be different with lifeforms from a different planet.”
Not just on a different planet. Humans do not understand a bee’s waggle dance. It took scientists to decode it.

^I’m aware of our ignorance of most of our own co-lifeforms, on this planet.
We don’t know much, about a LOT. There could be “aliens” living here, deep underwater.
Or maybe there are extraterrestrials walking amongst us, and we can’t detect them because our 5 senses are our limitation.

My understanding, is that AI will likely enable us to “understand,” and perhaps “communicate” with other animals. I don’t claim to fully understand how, but it sounds feasible considering what I hear/read about AI.

I guess it would hypothetically depend on what you mean by “telepathic”. When we “think” we do so “verbally” (internal voice) and pictorially (the beauty of a sunset). Along with all this comes emotions that we have developed throughout our lives. If a non-human lifeform came to Earth with telepathic powers, would they only be able to see what we were thinking or what we were feeling as well? If it was just what we were thinking, they could see all the pictures in our minds, but the inner voice would probably mean nothing to them.

^Well. Admittedly, I’m not an expert on telepathic abilities.
Like I said, I was thinking about people who say they were telepathically communicated with by aliens.
It occurred to me, though; how could they know to tell me in my language “I mean you no harm.”

There ARE people (of course,) who claim that telepathic communication is possible.
The language thing though, it seems like a sticking point.

But. IF it was possible, it would be extremely difficult to communicate what is intended to be communicated.

^Consider this, though: If there was a visitation by aliens and if they could communicate telepathically, their ability to understand things might be far more developed than we can consider. Much like our senses of smell and taste are tied together and enhance each other, their senses might be likewise developed differently. Telepathically reading lines of words out of someone’s mind might actually be something closer to reading the meanings that person associates with the words in his mind.

There’s no evidence that telepathy is possible. there’s no evidence that anyone’s ever been contacted telepathically (or otherwise for that matter) by extaterrestrial beings. Claims of receiving telepathic communication has the convenient property of being entirely unverifiable and also happens to be indistinguishable from mental phenomena such as delusions and hallucinations which we do have evidence for.

Or as @JLeslie nicely sumarized: “I’m going with no.”

If we’re talking about fiction and world-building, I think it might be fun to play with these distinctions. Have a character struggling with mental illness be the one that’s being contacted telepathically. That could be a very interesting story. Maybe their atypical neural configuration is better able to receive the telepathic communication?

^I did say “hypothetically.”