The Acoustical Study of Lexical Stress in Persian

This paper examines the effects of lexical stress on intensity and duration in Persian, both in the presence of the intonational prominence contrast, and in the abstraction from the compounding accent condition. A production study was conducted in which ten speakers produced Persian lexical and reiterant disyllabic minimal stress pairs spoken with and without an accent in a fixed carrier sentence. Duration, overall intensity, and spectral levels in four contiguous frequency bands were measured. Results showed a significant difference in overall intensity and spectral tilt between accented and unaccented syllables. However, no significant differences were found for these measures between stressed and unstressed syllables in the absence of the accent contrast. In contrast, duration proved the most reliable correlate of stress, as Persian speakers produced stressed syllables consistently longer than their unstressed counterparts independent of the accompanying intonational prominence contrast.