Effects of stop voicing on long-distance acoustics
Lisa Lipani · The Journal of the Acoustical Society of America · 2019
In Coleman (2003), the phonological feature [voice] was found to have a long-distance coarticulatory effect. However, voicing is not always realized as categorically present or absent. Davidson (2016) classifies partially voiced stops as having different patterns of voicing: bleed, trough, negative VOT, and hump. The present study answers the question: How do voicing patterns in stops affect the long-distance coarticulatory properties of the stop? Following the methodology of Coleman (2003), LPC coefficients, voicing, F0, harmonics-to-noise ratio, and z-score normalized RMS amplitude were measured in the read data from the Rainbow Passage in the Nationwide Speech Project (Clopper and Pisoni, 2006) in order to examine the stops and their coarticulatory effects. In the second sentence of the Rainbow Passage, the phones [b], [d], and [k] and their surrounding acoustics were measured in 10 millisecond frames that were aligned in time using dynamic time warping. A preliminary analysis using data visualization with smoothed conditional means reveals differences in the acoustics. There were several differences in both anticipatory and carryover coarticulation in the first through sixth and ninth through eleventh LPC coefficients. Subtle differences in acoustics as a result of long-distance coarticulation have implications for what makes both human and synthetic speech sound natural.