Two experiments were conducted in order to study the perceptual discrimination of syllable duration within sentences. Two natural French sentences each consisting of 8 syllables were re-synthesized with 15% increases and decreases in syllable duration up to ±60%. The modified stimuli were presented to subjects whose task was to judge how natural they sounded. The same stimuli were then used to determine whether the modifications in duration were perceptible. The results provide evidence of the fact that judgment of the rhythmic quality of sentences (a linguistic task) and temporal discrimination (a psycho-acoustic task) both have the same functional basis. The detection threshold for unstressed syllables was found to be lower than that of stressed syllables due to linguistic familiarity.
Bibliographic reference. Nishinuma, Yukihiro / Duez, Danielle (1989): "Perceptual optimization of syllable duration in short French sentences", In EUROSPEECH-1989, 2694-2697.