Phonological models of intonation use abstract categories, such as pitch accents, to build a bridge between continuous modulations in f0 contours (on the substantial side) and post-lexical meaning (on the functional side). However, recent research on Romance, Germanic and non-Indoeuropean languages shows that sentence modality contrasts (i.e. question vs. statement) are often realized not only with different f0 contours, but also through differences in individual phone duration or global speech rate. If these durational differences were also used as a cue in the perception of sentence modality contrasts, phonological categories in current models of intonation would qualify as excessively underspecified, and they should be expanded in order to include phonetic information on the temporal dimension as well. In this paper we evaluate the role of durational differences as a cue to the perception of sentence modality contrasts in the Neapolitan regional variety of Italian. Read sentences were resynthesized by switching durational and intonational patterns of questions and statements, and used in a forced-choice identification task. The results show that listeners exclusively rely on intonational cues, thus suggesting that, at least for this specific contrast in this specific variety, phonological representations of intonational contrasts do not need to be enriched with phonetic detail at the durational level.