The effect of stress and boundaries on segmental duration in a corpus of authentic speech (british English)

Research into the effect of stress and boundaries on segmental duration in speech has, for obvious reasons, most often been applied to carefully constructed sentences pronounced in laboratory conditions. The availability of a large labelled database of British English (Aix-Marsec) provides an opportunity to test different hypotheses concerning the factors influencing segmental duration from a corpus of authentic speech (defined as speech produced with the intent of communicating its meaning to the listener). In particular, in this paper, we look at the effect of stress and boundaries on prosodic structure in British English. Recent work has suggested that while word boundaries seem definitely to have a significant effect of the duration of segments, once the number of segments in the narrow rhythm unit is known, there is no orthogonal effect of word stress. In this study we look in particular at effects of word and intonation unit boundaries and at their possible interaction with stress and find that while intonation unit boundaries definitely affect segmental duration, no similar effect could be shown for word boundaries.