Regional Italian (, ) is any regional variety of the Italian language.
Such vernacular varieties and standard Italian exist along a sociolect continuum, and are not to be confused with the local non-immigrant languages of Italy that predate the national tongue or any regional variety thereof. Among these languages, the various Tuscan, Corsican and Central Italian lects are, to some extent, the closest ones to standard Italian in terms of linguistic features, since the latter is based on a somewhat polished form of Florentine.
The various forms of Regional Italian have phonological, morphological, syntactic, prosodic and lexical features which originate from the underlying substrate of the original language.
Regional Italian and the languages of Italy
The difference between Regional Italian and the actual languages of Italy, often imprecisely referred to as dialects, is exemplified by the following: in Venetian, the language spoken in Veneto, "we are arriving" would be translated into , which is quite distinct from the Standard Italian . In the regional Italian of Veneto, the same expression would be stémo rivando or siamo dietro ad arrivare. The same relationship holds throughout the rest of Italy: the local version of standard Italian is usually influenced by the underlying local language, which can be very different from Italian with regard to phonology, morphology, syntax, and vocabulary. Anyone who knows Standard Italian well can usually understand Regional Italian quite well, while not managing to grasp the regional languages.
Origin
Many contemporary Italian regions already had different substrata before the conquest of Italy and the islands by the ancient Romans: Northern Italy had a Ligurian, a Venetic, and a Celtic substratum in the areas once known as Gallia Cisalpina "Gallia on this side of the Alps"; Central Italy had an Umbrian and Etruscan substratum; Southern Italy and Sicily had an Oscan and Italic-Greek substratum respectively; and finally, Sardinia had an indigenous (Nuragic) and Punic substratum. These languages in their respective territories contributed in creolising Latin, the official language of the Roman Empire.
Even though the Sicilian School, using the Sicilian language, had been prominent earlier, by the 14th century the Tuscan dialect of Florence had gained prestige once Dante Alighieri, Francesco Petrarca (Petrarch) and Giovanni Boccaccio all wrote major works in it: the Divina Commedia, the Canzoniere and the Decameron. Italian, defined as such, began to spread and be used as a literary and prestigious means of expression across the whole peninsula, Sicily and Corsica in the late Middle Ages; on the other hand, it would be introduced to Sardinia by a specific order only in the second half of the 18th century (1760), when the island's ownership passed over to the House of Savoy. It was up to Pietro Bembo, a Venetian, to identify Florentine as the language for the peninsula in the Prose nelle quali si ragiona della volgar lingua (1525), in which he set up Petrarch as the perfect model. Italian, however, was a literary language and so was a written rather than spoken language, except in Tuscany and Corsica.
The popular diffusion of a unified Italian language was the main goal of Alessandro Manzoni, who advocated for a single national language mainly derived from "cultured" Florentine language. Having lived in Paris for many years, Manzoni had noticed that French (defined as the capital's dialect) was a very lively language, spoken by ordinary people in the city's streets. On the other hand, the only Italian city where even the commoners spoke something similar to literary Italian was Florence, so he thought that Italians should choose Florentine as the basis for the national language.
The Italian Peninsula's history of fragmentation and colonization by foreign powers (especially France, Spain and Austria-Hungary) between the fall of the Western Roman Empire and its unification in 1861 played a considerable role in further jeopardizing the linguistic situation. When the unification process took place, the newly founded country used Italian mainly as a literary language. Many Romance and non-Romance regional languages were spoken throughout the Italian Peninsula and the islands, each with their own local dialects.