Do you dislike your voice? I remember the shock I had when I heard myself on a tape recorder, I sounded nothing like the voice I heard myself speak with. I'm not too fond of it now, but I've learnt to accept it.
Maybe you prefer the sound of yourself singing? I don't, I like singing, but don't have a singer's voice; but maybe you do.
You could try elocution lessons to modify your voice, even if you have to wait until you're old enough to work and pay for the lessons.
If you feel you're being ignored or laughed at, maybe counselling will help you find out why this is and what to do about it (you could be trying too hard to fit in and making a lot of mistakes, for example).
In the meantime, you could find in outlet in art and/or writing. Maybe a diary, where you can write your thoughts, opinions etc, without having to worry about what others think - remember to hide it away where nobody will stumble on it, or keep in with you at all times, of course. If you don't want a printed diary with set space for each day, just use an ordinary notebook or ring binder, where you can use as much or as little space as you need to each time.
