Effects of intra-phrase position on acceptability of changes in segmental duration in sentence speech

Perceptual evaluation experiments were carried out on the acceptability of segmental duration change in a sentence. The intraphrase positional effects were systematically analyzed using synthesized speech stimuli in which one of the vowel segments was either lengthened or shortened. Statistical analyses showed that acceptability degradation due to duration changes was greater at the initial and medial positions than at the final position in a phrase. Further perceptual experiments suggested that the factors of speaking rate and breath grouping affected the variability of the intraphrase positional effects.