  Two types of consonant gemination characterize Italian: lexical and
syntactic. Italian lexical gemination is contrastive, so that two words may
differ by only one geminated consonant. In contrast, syntactic gemination
occurs across word boundaries, and affects the initial consonant of a word in
specific contexts, such as the presence of a monosyllabic morpheme before the
word. This study investigates the acoustic correlates of Italian lexical and
syntactic gemination, asking if the correlates for the two types are similar in
the case of stop consonants. Results confirmed previous studies showing that
duration is a prominent gemination cue, with a lengthened consonant closure and
a shortened pre-consonant vowel for both types. Results also revealed the
presence, in about 10-12% of instances, of a double stop-release burst,
providing strong support for the biphonematic nature of Italian geminated stop
consonants. Moreover, the timing of these bursts suggests a different planning
process for lexical vs. syntactic geminates. The second burst, when present, is
accommodated within the closure interval in syntactic geminates, while lexical
geminates are lengthened by the extra burst. This suggests that syntactic
gemination occurs during a post-lexical phase of production planning, after
timing has already been established.
