Effects of utterance position on English speech timing.

8 speakers of American English produced utterances consisting of one to five disyllables ([bábe] or [pápe]). Vowel and stop closure intervals were defined by variations in supraglottal pressure, sensed through a thin tube inserted in the mouth. Closure was always longer for /p/ than /b/ in utterance-medial positions. In utterance-initial position, however, /b/ lengthened more than /p/ so that no duration difference between /p/ and /b/ was observed. Utterance-initial position did not influence vowel duration. In contrast, utterance-final position affected only vowel duration, lengthening both final-syllable unstressed vowels and stressed vowels in penultimate syllables.