Synchronic patterns of Tuscan phonetic variation and diachronic change: evidence from a dialectometric study

A careful investigation of synchronic patterns of linguistic variation with underlying linguistic features can lead to important insights into the comprehension of diachronic phonetic processes. Starting from the analysis of synchronic patterns of phonetic variation in Tuscany we tackled one of the main and most debated features of Tuscan dialects, the phenomenon of spirantization with a specific view to the so-called Tuscan "gorgia" (i.e. voiceless spirantization). In particular, we showed that the newly proposed method of spectral partitioning of bipartite graphs applied to synchronic dialectal data can effectively be used to investigate diachronic phonetic processes. From a careful analysis of the sound correspondences involving voiceless and voiced stops, we tracked the evolution of the spirantization phenomenon in several respects. First, we tracked spirantization geographically, across Tuscany from the influential center of Florence to the peripheral areas. Second, we tracked it phonologically, from voiceless to voiced stops, and within each voicing class from velars to dentals and then to bilabials. Finally, we tracked it demographically, with young speakers using the most innovative sound correspondences more than old speakers. The fact that these results are in line with the literature on the topic of Tuscan "gorgia" demonstrates the potential of the method of spectral partitioning of bipartite graphs with respect to the reconstruction of diachronic processes starting from diatopically distributed synchronic dialectal data.