Letter: Effect of speaking mode on temporal factors in speech: vowel duration.

Abstract

Previous investigators have shown that vowel duration decreases as the number of syllables in a word increases, when carrier phrases constitute the material. Umeda [J. Acoust. Soc. Am. 52, 133(A) (1972)] found that, in connected text, factors other than the number of syllables in the word have stronger influence in vowel duration. It turned out that differences were very small, if present at all, in vowel duration in connected text material. This investigation was conducted to find whether the differences result from speakers' idiosyncracies or from different speech modes—carrier phrase reading and connected speech. Two subjects, one of whom served in Umeda's study, read lists of monosyllabic and polysyllabic words in carrier phrases. Measurements were taken on the duration of one vowel /æ/, in stressed syllables in words of varying length. Conditions also investigated were the position of the stressed syllable and the class of the following consonant. Analyses of variance were computed separately for each subject. Results from the carrier sentence material confirm previous findings of the decreased duration, at least up to three syllables. One subject, while showing the characteristic shortening in vowel duration in the carrier phrase mode, exhibited almost no differences in duration of the vowel in connected text. Apparently the dependence of vowel duration on number of syllables is one of the dominating factors in the carrier phrase mode, but is a negligible factor in connected speech.