Language, we use it, we know it, it's pretty good. Allows us to take the thoughts from inside our heads and sort of shploot them into existence the physical world as vibrations in the air.
Dude how wild is that shit, we can use our mouth to vibrate the air in specific patterns. Then other people use there ears which we just happened to have, to sense those vibrations and input electrical signals to the brain that corresponds to words we learned that have definitions, which are just more words.
How the fuck did they invent the first word? Was it just sounds and people kept using the same sounds for the same thing, like if a lion was near we'd go "EEEEOOOOK" and people just started associating that with a lion... Wait, the sound the probably made was "lion" not "eeeook". Never mind, I figured it out. I understand how language got invented now, it actually makes a lot of sense. The universe is pretty tight, I glad we exist... at least I think I am... I have nothing to compare it to so no way to be certain.
If a blind guy and a deaf guy were both sitting at a bar, would they even know the other was there?