@article {347, title = {Prosody - a missing link between phonetic detail and phonemic categories?}, year = {2007}, publisher = {Nederlandse Vereniging voor Fonetische Wetenschappen}, address = {Nijmegen, The Netherlands}, abstract = {

The prosodic structure of an utterance influences the fine-grained phonetic details of spoken word forms. Speech sounds are articulated more strongly in prosodically prominent positions, e.g., at the onsets of higher prosodic domains.

Importantly, this prosodic strengthening involves phonetic characterisitcs of the speech signal which also cue phonological distinctions. While articulatory strengthening suggests that, e.g., a prosodically strong /b/ would become more similar to a [p] (what I will call the {\textquoteleft}Fortition Account{\textquoteright}), it has also been hypothesized that prosodic strengthening enhances language-specific distinctive features, which would make a prosodically strong /b/ less [p]-like. We investigated how domain-initial strengthening affects the acoustic cuees to phonemic contrasts in German obstruents.

Experiment 1 focused on the plosives /b, p, d, t, g, k/, which form pairs of phonemes differentiated by the fortis-lenis contrast. Important acoustic cues to this contrast are closure duration, glottal vibration during closure, voice onset time, and intensitiy of the release noise. Closure durations were longer At higher prosodic boundaries, closure durations were longer, and in lenis plosives, a smaller proportion of the closure was produced with glottal vibration. Voice onset time in lenis plosives was not affected by prosody. In contrast, VOT decreased at higher boundaries for the fortis plosives, as did the maximal intensity of the release. These results suggest that the effects of prosody on different phonetic cues can go into opposite directions, but are overall constrained by the need to maintain paradigmatic phonemic contrasts.

In Experiment 2, we examined how prosody constrains a sandhi process, the progressive assimilatory devoicing of the word-initial lenis fricatives /v, z/\  folllowing /t/. Reduction in glottal vibration makes lenis fricatives more fortis-like (/f, s/). This devoicing was especially strong across small prosodic boundaries. However, prosodic structure affected the fricative duration, another cue to the fortis-lenis distinction, in the opposite direction. Duration was shorter at smaller boundaries, just as the closure duration of the plosives. Hence, at smaller prosodic boundaries, fricatives were more devoiced (more fortis-like), but also shorter (more lenis-like).

In conclusion, our results show that neither the Fortition Account nor the Feature Enhancement explanation are fully supported by the syntagmatic effects of prosody on individual cues. At the phonemic level, however, the paradigmatic fortis - lenis contrast remains distinctive in all prosodic contexts, irrespective of prosodic strengthening and assimilation.

}, author = {Claudia Kuzla} }