Just-language, without any irl stuff, probably doesn’t really achieve communication. Because the words don’t carry their definition. And they definitely don’t carry any real experience-stuff (sight, sound etc) either.
It’s just assumed that you’re connecting the word to the definition/experience, in your head, in a way that makes communication happen.
And that’s a big assumption. It might be only 80% congruent. Or 50%. Or 5%. We could be a race of Chinese boxes for all we know.
IRL there is a verification to the process. If I order a pizza and I get a pizza then that’s a pretty good sign that the communication is working.
But on the Internet, where it’s just-language? Forget it. Howling solipsists all the way down.
In common communication the shared fantasy is treated as equivalent to experience.
Not in science though. Science (and science-like things) is an exception there. Science has the providence-thing (you could say that it explicitly acknowledges that language isn’t enough). I’d say that’s the source of its power.