Effects of Speaking Rate on the Singleton/Geminate Consonant Contrast in Italian

Abstract A production and a perception experiment were conducted to investigate the effect of speaking rate on the singleton/geminate consonant contrast in Italian. Acoustic analyses were performed of labial and dental singleton and geminate consonants produced in words spoken in isolation and in a sentential context at both a slow and a fast rate of speech. Closure duration was found to discriminate between the two categories of consonants within a given speaking rate. For one speaker, at a fast speaking rate the distribution of closure duration of geminate consonants was identical to the distribution of closure duration of singleton consonants produced in isolation. However, a measure reflecting the relation between two durations, the ratio between consonant duration and preceding vowel duration, discriminated between singletons and geminates both within and across speaking rates. The perception experiment tested whether manipulation of the consonant to vowel ratio would result in perceptual shifts. Results indicated that changing the ratio did affect perception of the geminate/singleton distinction. However, these effects varied greatly across listeners. Taken together, these findings provide support for the view that there are stable acoustic properties corresponding to phonetic features in that even though one type of temporal information, closure duration, is greatly affected by changes in speaking rate, a higher-order relational measure remains constant.