Phonetica Editor: K. Kohler, Kiel Separatum Publisher: S. Karger AG, Basel Printed in Switzerland J. Caspers V J. van Heuven Holland Institute of Linguistics, Department of Linguistics/Phonetics Laboratory, Leiden University, Leiden, The Netherlands Phonetica 1993; 50:161-171 Effects of Time Pressure on the Phonetic Realization of the Dutch Accent-Lending Pitch Rise and Fall Abstract The goal of this experiment is to find the most important pho- netic features of Dutch accent-lending pitch movements, in terms of shape, pitch level and alignment with the segmental structure. Time pressure is used äs a heuristic method to isolate important phonetic aspects of pitch movements, assuming that under time pressure the Speaker will preserve those aspects. In a production experiment, accent-lending rises (T) and falls ('A') were realized under various types of time pressure. The pitch rise is time-compressed under all pressure types, which would mean that the shape of the rise is relatively unimportant. The segmental alignment of the rise proved to be more impor- tant: the onset of the rise is synchronized with the syllable on- set. For the fall no fixed synchronization point was found, but its shape was relatively invariant, indicating that shape rather than exact timing is the more important feature of the fall. Introduction A Question of Methodology It has often been observed that speech is a redundant code: it contains more detail than is normally needed for successful communica- tion. Much phonetic research has been aimed at distinguishing the relative communicative importance of the various properties of spoken utterances. This type of research is motivated by scientific curiosity per se, but its results can readily be used in technological applications. For example, if the designer of a text-to- speech System, limited by memory space and processing capacity, has to make a choice äs to which properties to include in his talking ma- This rosoarch was supported by tho Received: Linguistic Research Foundation, which is March 8th, 1993 funded by the Netherlands Organization for Accepted: Scientific Research, NWO, under project June 3, 1993 Nr W 173 (W J. Caspers © 1993 Department of S. Karger AG, Basel Linguistics/Phonetics Laboratory 0031-8388/93/ Leiden University, PO Box 9515 0503-0161 $2.75/0