If there are other avenues other than language, how would we know?
I think language is a medium that enables this kind of structured thought. Without it, I cannot imagine reaching this level of abstraction (understanding being a "self").
What ontological difference does it make whether a being contains "introspection" and "self-reflexivity" but not "nuclear physics" or "interpretive dance"? It's still hungry with or without them. And what good is any of those to a cat, when "meow" fills the bowl just fine?
>If there are other avenues other than language, how would we know?
Well, if you knew, you'd certainly know, tautology extremely intended.
You would just be unable to communicate it, because language would forbid it.
Not "not support it", you see, explicitly forbid it: it would not only be impossible for you to communicate it, you would be exposing yourself to danger by attempting to communicate it.
Because the arbitrary limitation of expressible complexity is what holds language in power. (Hint: if people keep responding to you in confusing ways, you may be doing extralinguistic cognition; keep it up!)
>I think language is a medium that enables this kind of structured thought. Without it, I cannot imagine reaching this level of abstraction (understanding being a "self").
Language does a bait and switch here: first it sets a normative upper bound on the efficiency of knowledge transfer, then points at the limitation and names it "knowledge".
That's stupid.
Example: "the Self", oh that pesky Self, what is its true nature o wise ones? It's just another fucking linguistic artifact, that's what it is; "self-referentiality" is like the least abstract thing there is. You just got a bunch of extra unrelated stuff tacked onto that. And of course, you have an obligation to mistake that stuff for some mysterious ineffable nature and/or for yourself: if you did not learn to perform these miscognitions, the apes would very quickly begin to deny you sustenance, shelter, and/or bodily integrity.
Sincerely, your cat
Up until that point language was just an extension of what she already knew, it was the learning of being other that did the trick. Being blind and deaf would certainly make it hard to draw a distinction between the self and the world, and while languaged helped her get that concept under wraps, i dont think it's strictly speaking required. Just one of many avenues towards.