Interspeech'2005 - Eurospeech
This study investigates whether the stress foot is a planned timing unit in American English, by examining the durational characteristics of the foot in three different prosodic contexts - i) within an intermediate phrase, ii) across an intermediate phrase and iii) across an intonational phrase. The results show that as the number of syllables in a foot increases, the duration of the foot increases, but the mean duration of syllables is reduced. Our examination of the internal structure of the foot reveals that there is a consistent shortening of stressed syllables within an intermediate phrase. These findings indicate that the stress foot within the intermediate phrase is a timing unit where durational shortening occurs in compensation for an increase in syllable count within the foot.
Bibliographic reference. Kim, Heejin / Cole, Jennifer (2005): "The stress foot as a unit of planned timing: evidence from shortening in the prosodic phrase", In INTERSPEECH-2005, 2365-2368.