I can read silently perfectly well, and I can do it very fast and still understand everything. But when it comes to reading out loud, whether it’s by myself or to an audience, I just can’t do it. I don’t understand a thing, and I stumble over everything. I just don’t get a thing when I read out loud. I have to read very, very slowly so I won’t stumble over as many words. But, like I said, it’s only reading out loud that I struggle with, and I can read silently perfectly well. Is this normal, and the people I’ve talked to who don’t have this problem are weird? Or is it some form of speech impediment or something (which, by the way, I don’t have a speech impediment other than a very slight stutter when I’m excited)?
I would guess stage fright, brought on by someone interrupting you at every little mistake. That is very common, but usually only if you are actually on stage. See if your school has a drama class where you can practice story telling or any vocal skill. You can work alone by copying story tellers on youtube. Search "aaron wilburn" and "jerry clower" to get stories to copy.
The main thing you will learn in an actual class is how to project your voice. You need somebody to show you what that means and how to do it.
I would suggest practicing reading out loud as soon as possible when you're on your own. Just try to focus on what you're reading when reading out loud. When you will notice the progress, you may try reading out loud for your cat or dog, or stuffed animals. If that's an excitement that causes your struggle with reading out loud, you won't feel uncomfortable and will get used to it. Later you can try reading out loud for your family or close friends, and after you get used to this, for a bigger group of people. Hope this will help.