Il vocalismo tonico pisano e livornese. Aspetti storici, percettivi, acustici.

The work is an acoustic study of the stressed vowel systems of four locations in Western Tuscany (Livorno, Pisa, Cascina, Cecina) that have articulatory characteristics not present in the Central Tuscan vowel system, such as the velarization (backing) of the low vowel /a/ and a general lowering of stressed mid vowels. The working hypothesis of this study is that the city of Livorno is the epicentre of these particular articulations (specifically lowering); young speakers of the other three locations have adopted specific characteristics of the Livornese vowel system as a social marker that signals group identity. We present the results of an acoustic study of a speech corpus from twelve male subjects and twelve female subjects (six for each location, divided into three age groups) which has minimal diaphasic variation (register variation). The seven stressed vowels under consideration were inserted in a target word which was read in isolation and in internal and final position in a carrier phrase. Vowel duration, and first and second formant frequencies were measured. We describe the most typical vowel system on the basis of statistical analyses and graphical representations, and we turn our attention to the duration and fundamental frequency modulation relationship. Finally we express some hypotheses on the historical time frame and the origin of the phenomena (concerning this we use also data from linguistic atlases). We also trace some possible directions for future research, from a point of view which joins acoustic research with dialectology and sociolinguistics studies.