Effect of Duration upon Vowel Identification
Kenneth Noble Stevens · The Journal of the Acoustical Society of America · 1959
The purpose of this experiment is to determine the extent to which both duration and formant frequencies play a role in the identification of American English vowels. A resonance analog synthesizer was used to generate a number of cvc syllables in which the initial and final consonants were always /d/ and /s/, respectively. The durations of the vowels were given values from 20 to 500 msec. Two series of stimuli were recorded and were presented to listeners in random order. In the first test the frequencies of the first three formants of the vowel varied in several steps to encompass values appropriate for the front vowel series /iɪɛæ/, and the listeners were asked to identify the vowel as one of these; in the second test the back vowels /uᴜʌɑ/ were studied. The results indicated that the /iɪ/ and /uᴜ/ distinctions are affected only slightly by vowel duration whereas the distinctions /ɛæ/ and /ʌɑ/ are strongly influenced by duration. In a similar experiment in which the stimuli were mixed with noise, the influence of vowel duration was even more marked. The results are discussed in the light of existing data on vowel perception. (This research was supported in part by the National Science Foundation.)