My GameVoice works in other games, but not in Prophecy. It recognizes the commands (i hear them echoed back to me) but the keystrokes don't get picked up by the game.
I donwloaded the Version 1.5 patch from gamevoice.com and now the commands are sent to the game. It takes some adjustment to spell and then pronounce words in a way that ensures phonetic matching, but it is fun once you get it working. For example, you can map Alt-T to "phuhkyu" or "biteme slymo"