My screen reader voice... changed

I am blind, so I am using a screen reader, a program which reads text on the screen by using a computer voice. With that out of the way, I was editing a documment, what kind of documment it is is not important to put it simply it was a test. While I was solving problems on that test, the curser often changed it's position, for what seemed like no reason at all. Eventually it jumped to the last problem for whatever reason, and I decided, after trying to go up back to the problem I had been before, I decided to do the 14th out of 20 problems on the tests. At that moment, the screen reader voice became raspy. I tried changing the setings, but nothing.