It just started happening today, after I've had the new update for it for weeks. I open my text-messaging app, starting typing with the slide-out keyboard, and it brings up the text predictor, then freezes the app; and the text-predictor bar remains there. I can't get rid of it until I restart the phone.
(Verizon's my provider, I've had the phone since March of this year, um... I don't know what other information you need.)
Try turning off text prediction for the hardware keyboard. On the software keyboard hold down the voice key and then go to settings, scroll down to device keyboard and turn off show suggestions and auto correct errors, or just one and see if that helps. You may also want to try an entirely new keyboard app, that might also work.