  All Italian consonants affected by gemination, that is affricates,
fricatives, liquids, nasals, and stops, were analyzed within a project named
GEMMA that lasted over a span of about 25 years. Results of the analysis on
stops, as published in (Esposito, A., and Di Benedetto, M. G. (1999). "Acoustic
and Perceptual Study of Gemination in Italian Stops," The Journal of the
Acoustical Society of America, ASA, Vol. 30, pp. 175-185) showed that the main
acoustic cue to gemination in Italian was closure duration, while frequency and
energy domain parameters were not significantly affected by gemination. This
paper - the first of a set of two covering all remaining consonants - addresses
nasals and liquids; its companion paper addresses affricates and fricatives.
Results on nasals and liquids confirm the findings on stops, in particular that
the primary acoustic cue to gemination in Italian is durational in nature and
corresponds to a lengthened consonant duration. Results also show an inverse
correlation between consonant and pre-consonant vowel durations which is,
however, also present when considering singleton vs. geminate word sets
separately, indicating a sort of duration compensation between these segments
to eventually preserve rhythmical structures; this inverse correlation is
reinforced when considering singleton and geminate sets combined.
Classification tests of singleton vs. geminate consonants show that, for both
nasals and liquids, best classification scores are obtained when consonant
duration is used as a classification parameter. Although slightly less
performing, the ratio between consonant and pre-consonant vowel durations is
also a potential good candidate for automatic classification of geminate vs
singleton nasals and liquids in Italian.
