Abstract
In certain languages, vowel quality changes in unstressed syllables. In acoustic phonetics, this characteristic, namely vowel 'undershoot' under certain conditions and the tendency to centralize, is referred to as 'vowel reduction'. Previous researches have shown that Persian vowel space reduces and ...
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In certain languages, vowel quality changes in unstressed syllables. In acoustic phonetics, this characteristic, namely vowel 'undershoot' under certain conditions and the tendency to centralize, is referred to as 'vowel reduction'. Previous researches have shown that Persian vowel space reduces and is centralized in unaccented syllables and as a result have considered the change in vowel quality to be an acoustic correlate of lexical stress in Persian. The present paper is an investigation of the effect of stress on the duration and quality of simple vowels in accented and unaccented open syllables of bisyllabic words in the speech of 14 female and male speakers of Persian. Results showed a reduction of vowel duration in unaccented syllables, but no reduction or centralization of vowel space. Rather, the vowel space was larger in unaccented syllables. Vowel quality changed, but this change was not statistically significant for all vowels. Previous research has shown that a reduction in vowel duration is not necessarily accompanied by vowel undershoot, as articulators can move faster to achieve ideal vowel quality under time limitations. Thus, vowel reduction cannot be considered as an acoustic correlate of lexical stress in Persian, since besides stress, many other factors, including speaking style, syllable type, word length and type, influence vowel quality.
