  Consonant gemination in Italian affricates and fricatives was investigated,
completing the overall study of gemination of Italian consonants. Results of
the analysis of other consonant categories, i.e. stops, nasals, and liquids,
showed that closure duration for stops and consonant duration for nasals and
liquids, form the most salient acoustic cues to gemination. Frequency and
energy domain parameters were not significantly affected by gemination in a
systematic way for all consonant classes. Results on fricatives and affricates
confirmed the above findings, i.e., that the primary acoustic correlate of
gemination is durational in nature and corresponds to a lengthened consonant
duration for fricative geminates and a lengthened closure duration for
affricate geminates. An inverse correlation between consonant and pre-consonant
vowel durations was present for both consonant categories, and also for both
singleton and geminate word sets when considered separately. This effect was
reinforced for combined sets, confirming the hypothesis that a durational
compensation between different phonemes may serve to preserve rhythmical
structures. Classification tests of single vs. geminate consonants using the
durational acoustic cues as classification parameters confirmed their validity,
and highlighted peculiarities of the two consonant classes. In particular, a
relatively poor classification performance was observed for affricates, which
led to refining the analysis by considering dental vs. non-dental affricates in
two different sets. Results support the hypothesis that dental affricates, in
Italian, may not appear in intervocalic position as singletons but only in
their geminate form.
