The interdependence of tonal and durational cues in the perception of rhythmic groups.

This experiment investigated whether rising fundamental frequency (f0) and increased duration are interdependent perceptual cues to rhythmic groups in speech, and whether this depends on listeners' native language. In a two-alternative forced- choice decision task, listeners had to indicate whether they perceived a 3 + 2 or 2 + 3 grouping in 5- syllable- long series of various digits and letters, in which f0 and duration were manipulated in the second and/or third syllable. The listeners were native speakers of Swiss German, Swiss French, or French. These languages differ from each other in terms of prosodic properties involving f0 and duration. The results demonstrate that rising f0 and increased duration are interdependent cues to rhythmic groups, since the two cues were significantly more effective than one when heard simultaneously, but significantly less effective than one when heard in conflicting positions around the rhythmic- group boundary location. Moreover, listeners' native language influenced whether f0 or duration was the more effective cue. These findings are important not only for their insight into the perception of prosodic groups in speech, but also because they have implications for current research on speech rhythm.