Höhle, B. , Wellmann, C. , Holzgrefe, J. & Wartenburger, I.
University of Potsdam
This paper presents research on German infants? development of prosodic boundary detection. Six- and 8-month-olds? sensitivity to frequent prosodic boundary cues, i.e. pause, pitch and lengthening as single or coordinated cues was tested using behavioral and ERP measures. Short auditory stimuli that consisted of three coordinated names (e.g. Manu and Lilli and Mona) were presented with or without acoustic cues indicating a prosodic boundary after the second name. In naturally produced sequences these boundaries were marked by pause, a pitch rise and lengthening. By acoustic manipulations stimuli were created in which these cues either occurred in combination or in isolation. Using the head turn preference procedure we found that 6-month-olds only detected the boundary when it was marked by all three cues. In contrast, 8-month-olds also detected boundaries marked by a combined pitch rise and lengthening but not those solely marked by a pitch rise. However, ERPs recorded in 6-month-olds while presented with the same materials revealed a positive deflection for stimuli with combined pitch rise and lengthening but without pause - a pattern that did not occur with sequences that only contained a pitch rise or none of the prosodic boundary cues under consideration. This pattern mirrors ERP effects found in adults, where a so-called closure positive shift (CPS), reflecting the perception of a major prosodic boundary, was also found for the combined pitch and lengthening cue, but not for the sole pitch cue. It is corroborated by behavioral findings from adults and a corpus analysis which showed that boundaries solely marked by pitch are not treated as such by German adult listeners and that prosodic boundaries marked by pitch plus final lengthening are the most frequent boundary type in spoken German. Overall these data support the assumption of an early language-specific cue-weighting in the perception of prosodic boundaries.