The Pairwise Variability Index: rhythmic values from Italian Dialects and Language Typological Implications

old_uid4479
titleThe Pairwise Variability Index: rhythmic values from Italian Dialects and Language Typological Implications
start_date2008/03/31
schedule10h-12h
onlineno
summaryIn traditional views of rhythmic typology the rhythmic classification of a language was considered a given ‘primitive’, an inherent property of the language. In contrast, more recent studies see it as an emergent property, a product of both the phonotatics of the language and phonetic processes in production (Dauer 1987, Nespor 1990). Syllable complexity, possibly vocalic and consonantal length distinctions, stress-dependent vowel reduction and the propensity for phonetic vocalic and consonantal reduction processes (‘schwa-isation’, weakening and elision, etc.) during speech are considered contributory factors to the rhythm of an utterance, and via this to the general rhythmic impression of a language. Critically, rhythm not only becomes measurable (Ramus et al. 1999, Grabe-Low 2002, Barry et al. 2003, Russo-Barry to appear) as a speech phenomenon rather than an inherent language property, but it also necessarily becomes a continuous rather than a categorical property. A comparison of Standard Italian and Southern Italian dialects is carried out using acoustic measures related to structural properties: Vowel-interval and consonantal inter-vowel-interval durations are used to obtain rhythmic measures based on a number of approach. Italian is usually considered to be ‘syllable-timed’: it has a relatively simple (CV-dominated) basic syllable structure, no phonological vowel length opposition and no phonological vowel reduction. On the other hand, it has a consonantal length distinction, and pronounced allophonic tonic-vowel lengthening. The structural features found in the dialects offer support for a divergence from the traditional assumption of syllable-timing. Distributional observations and durational measurements of tauto- and heterosyllabic VC sequences show that make a strictly syllable-timed rhythmic structure untenable. Phonetic and phonological evidence is presented to support the interpretation of Italian dialects as a stress-timed language. Although much of the dialect observations place the stress-timing evidence at the systemic rather than the realisational level, the non-systemic, ‘performance’ evidence points in the same direction. Rhythm measures are calculated according to Ramus et al. 1999, Grabe-Low 2002, Barry et al. 2003, Russo-Barry to appear. The Ramus measures are (i) the proportion of vowels in the interpause streches ips (%V), (ii) the standard deviation of the Vowel duration in the ips (delta V) and (iii) the standard deviation of the intervocalic consonantal interval (delta C). The Grabe and Low measures correspond in essence to the Ramus variability measures, but are calculated in pairwise steps through the ips rather than globally across the ips. They are therefore called ‘Pairwise Variability Indices’ (PVIs). The difference (i) between consecutive vowels and (ii) between consecutive intervocalic intervals are averaged over the ips, giving a vocalic and consonantal variability measure. In the case of the vowel intervals, the difference is related to the sum of the two vowels. This ‘normalisation’ is claimed to be necessary (and possible) for the vowel intervals in order to counteract shifts in tempo because vowels vary more than consonants with tempo, and there is never more than one vowel ina vowel interval. We also present syllabically based PVI measures (PVI-Syll). It should be pointed out that, while capturing sequential variation, the PVI fails to maximise this possible advantage over the Ramus measures because vowel and consonant variation are calculated separately. The combined effect of vocalic and consonantal structure on an auditory rhythmic pattern is therefore not taken into consideration. PVI-Syll takes the consonant and vowel intervals together, reflecting the combined complexity of consonantal + vowel groupings in sequence within an interpause stretch. In agreement with predictions derived from phonological observation, the results of the above measures show a ‘rhythm plot’ in which the PVI-V and the PVI-Syll place the Italian dialect speakers nearer to the ‘stress-timed’ languages than traditional typology statements would lead one to expect. References Asu, Eva Liina / Nolan, Francis (2005) “Estonian rhythm and the Pairwise Variability Index”, Procedeengs Fonetik 2005, Department of Linguistics, Götemborg University, 29-32. http://www.ling.gu..se/Konferenser/fonetik/2005. Barry, William John /Andreeva, Bistra / Russo, Michela / Dimitrova, Snezhina / Kostadinova, Tania (2003) “Do Rhythm Measures Tell us Anything about Language Type?”, Maria-Josep Solé / Daniel Recasens / Joaquin Romero (eds.), Proceedings of the 15th Internaional Congress of Phonetic Sciences, Barcelona, 3-9 August 2003, Barcelona: Causal Productions Pty Ltd, 2693-2696. Dauer, M. Rebecca (1987) “Phonetic and phonological components of language rhythm”, 11th International Congress of Phonetic Sciences. Tallinn, Estonia: U.S.S.R. / Academy of Science of the Estonian S.S.R., vol. 5, 447-450. Grabe, Esther / Low, Ee Ling (2002) “Durational Variability in Speech and the Rhythm Class Hypothesis”, in Carlos Gussenhoven / Natasha Warner (eds.), Papers in Laboratory Phonology VII. The Hague: Mouton de Gruyter, 515-546. Nespor, Marina (1990) “On the rhythm parameter in phonology”, Roca Iggy M., (ed.), Logical Issues in Language Acquisition, Dordrecht: Foris,157-175. Ramus, Franck / Nespor, Marina / Mehler, Jacques (1999) “Correlates of linguistic rhythm in the speech signal”, Cognition 73, 265-292. Russo, Michela / Barry, William John (to appear) “Isochrony reconsidered. Objectifying relations between Rhythm Measures and Speech Tempo”, Speech Prosody 2008, 4th Conference on Speech Prosody, Campinas, May 6-9, 2008, Brazil.
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