Pre-boundary lengthening (PBL) is a widely attested “phenomenon whereby segments immediately before certain linguistic boundaries are longer than segments earlier in the utterance” (Gussenhoven & Rietveld 1992: 283). PBL is a complex phenomenon: first, it has been shown that PBL is absent or only marginally present in infant speech; second, there is inter-speaker variation in regard to the presence and amount of PBL. Thus, PBL most likely is a mechanism that is learnt by speakers. Furthermore, it has been found that PBL is implemented in language-specific ways, which raises the question whether and how it is linked to the word-prosodic system of a language. Despite the existence of PBL in various languages and its attested relevance for perception in adults and children, questions concerning the delineation of its domain of application, its temporal dynamics, and its cross-linguistic differences remain unanswered. The project sets out to test different hypotheses concerning the domain of PBL from a cross-linguistic perspective, investigating German, French, and Tswana. It ultimately addresses the question whether PBL is a universal production process, or whether its dynamics are language-specific, possibly linked to features of the word-prosodic system of a language.
Understanding the dynamics of PBL may provide insights on the mechanism for the computation of duration in speech. The insights gained also have direct relevance for a better understanding of the perception of PBL in guiding the development of hypotheses about how listeners exploit temporal patterns for the detection of prosodic boundaries. Lastly, the results of the project can also contribute to research on cognitive grouping beyond speech prosody, such as visual grouping or musical phrasing. Since the marking of a boundary by means of lengthening is not specific to speech, patterns of PBL in speech production may also be present in other modalities that involve cognitive grouping.