Importance and predictability each have been argued to contribute to acoustic prominence. To investigate whether these factors are independent or two aspects of the same phenomenon, naive participants played a verbal variant of Tic Tac Toe. Both importance and predictability contributed independently to the acoustic prominence of a word, but in different ways. Predictable game moves were shorter in duration and had less pitch excursion than less predictable game moves, whereas intensity was higher for important game moves. These data also suggest that acoustic prominence is affected by both speaker-centered processes (speaker effort) and listener-centered processes (intent to signal important information to the listener).