There is far more to reality/existence as a whole than humans can comprehend dude. The observable universe, perhaps a minute aspect of existence as a whole, has existed for billions of years, while humans have existed for at most a million. The self exists beyond and totally encompassing humanity, language and perception, I am not talking about the human psyche when I say "self", how arrogant and anthropomorphising that would be. Although it may feel like it, existence doesn't exist just for humans to wander around and meaninglessly play. Existence is very serious business, if anything.
Of course, to say "underlying" is not quite accurate for reality is simply in our face at all times and places. However the illusions we have about it are what veil it from us and hence, it's "underlying". What I mean by the "underlying" knowledge then is knowledge of the nameless flow of existence. You don't need language for that, every living creature grasps it to an extent. We use language to break it down into manageable bits and because of that humanity has taken over the world. But it also veils it from us, something that we could once clearly see as a species. The flow IS language, it's communication, learning, knowledge. You know the flow inside out but to encompass it with words is impossible for it is the sculptor of words.
When you differentiate with words between one object and another, you lose clarity. You forget the incredible complexity of the things you are referring to and you objectify and box them up into your limited knowledge & perception, allowing ignorance to be born. And suddenly the world becomes anthropomorphic. You have to remember that Earth itself is like a miniscule sand grain in a gigantic beach, we are disposable. The self is not disposable, the self is what does the disposing & reusing.