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, naïve participants played a verbal variant of play 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).

It is widely assumed that prosodically prominent words play a role in signaling the information status of entities in a discourse (Chafe, 1974; Bolinger, 1986; Prince, 1981; Jackendoff, 1972; Pierrehumbert & Hirschberg, 1990). For example, the word violin in (1b) receives emphasis, and this is related to it being the information requested by the speaker.

What does Alessandra play?

Alessandra plays the VIOLIN.

Although information status is clearly related to whether or not a word receives a pitch accent, the nature of this relationship is less clear. Two different factors have been claimed to provide an account of this relationship: 1) the importance of the information to the goals of the interlocutors and 2) the predictability of the information in a given context.

Bolinger (1972, 1986) argued that the most informative words in a sentence receive an accent and some version of this view has been used to understand differences in accent type (e.g. Pierrehumbert & Hirschberg, 1990) as well as the ways in which prominence signals the information structure of a sentence (e.g. Gussenhoven, 1983; Selkirk, 1996; Schwarszchild, 1999). The word “violin” in (1b) receives an accent because, as the answer to the question in (1a), it is the most important part of the sentence.

Researchers have also argued that acoustic phenomena associated with pitch accenting, especially duration, are a function of how predictable information is in a discourse. Words that are statistically predictable from the preceding linguistic context tend to be produced with shorter duration (Bell et al., 2003; Gregory et al., 1999). In addition, Gregory (2002) found that words were more likely to be produced without a pitch accent when they were predictable given their context. Related findings have shown that words that are in predictable contexts tend to have lower intelligibility (e.g. Bard & Aylett, 1999; Lieberman, 1963; Fowler & Housum, 1987), which is associated with a reduction in duration.