Arthur S. House
IDA Ctr. for Commun. Res., Princeton, NJ 08540
Kenneth N. Stevens
MIT, Cambridge, MA 02139
Measurements have been made on a corpus of bisyllabic nonsense utterances spoken by three adult male talkers on two occasions separated by 30 years. The 1960 and 1990 recordings were processed similarly so that comparisons could be made directly. Some primary and secondary characteristics of vowels were measured: duration, fundamental frequency and the frequencies of F1 and F2. The durations of prestressed consonants were measured, and vowel--consonant amplitude ratios computed. Long-term spectra of the talkers were examined and some informal listening comparisons were made. Spectrograms of some samples were studied, and statistical analyses, when appropriate, were made. Results indicate that the talkers' productions were remarkably consistent over 30 years. Over time the talkers' mean vocalic duration (10 vowels) shortened (6 ms); their mean vocalic fundamental frequency rose (7 Hz); their mean frequencies of F1 and F2 (10 vowels) descended (15 and 26 Hz, respectively); their mean (initial) fricative duration lengthened (12 ms); and, their mean (initial) stop duration lengthened (hold portion, 15 ms; release portion, 5 ms). Interactions were usually significant: individual talkers' changes in duration, formant frequencies; and fundamental frequency were not identical. Patterns of duration and fundamental frequency in the set of vowels, however, were stable over time.