Guys why do we yawn? Whenever I google it, I always get the same response (that we don't know why we do it) so what's. Your theory?

I just think it's something simple, really. Whenever you yawn, your hearing suddenly receives a "buff" for a period of time, when everything becomes louder. In nature hearing is really important, and when you're sleepy you may become more distracted to the point of ignoring things around you; deaf, if you will. So to keep that from happening our body makes us yawn. As for why we open our mouth: well, maybe it could to send a signal to others around us like a reminder to also yawn and keep a high alert (and also explain why yawning spreads to others) or maybe its something more weird like: ever noticed how some people move their ears when talking? Maybe there's some relation? I know its dumb, and I'm dumb and this whole thing is dumb and I'm no expert on anything here, but I'm really bored and could really use a discussion rn to distract myself. So, lets talk yawning, and maybe throw other weird shit our bodies do that we don't fully understand into it?