Quest for Glory 4 has a speech pack (resource.aud) which needs to be correctly pointed at by resource.cfg.
If you have the file, then you should put it in the same directory as the game and modify your resource.cfg to reflect that - change the line to "resAUD = .\" without the quotes.
If you don't have the file then you need to turn off speech, which as far as I know has to be done from the in-game menu. Go to the save/load menu, and turn off the "audio" option.
What's happening is that the game thinks you have the speech pack, and so is trying to reference that every time it brings up a dialogue box. Ordinarily it waits until the narrator has finished talking, but since you don't have it set up correctly there's no sound to wait for. Thus, speedy text.
I hope that helps. 😀