Historical Background of Standard Italian
When considering the history and development of the Italian language, a major turning point was the publication, in the early 1300's, of Dante Alighieri's monumental epic poem La Divina Commedia (The Divine Comedy). As Britten Milliman points out in La Vulgata Dantesca: Dante as Poet, Dante as Linguist: "Dante wrote La Divina Commedia in the Florentine version of Vulgar Latin. He wanted to be able to present his work to his contemporaries and felt compelled to defend the legitimacy of Florentine as a culturally elevated language."
According to Milliman, "Dante was steadfast in his linguistic views and even went as far as presenting these views in another lesser-known work called De Vulgari Eloquentia ("Concerning Vernacular Eloquence"), which was the first theoretical discussion of the Italian literary language."
Fast forward to the Cinquecento (the 16th century), when Pietro Bembo of Venice published his Prose della volgar lingua ("Writings on the Vulgar Tongue") in 1525. In this work, which was one of the first historical Italian grammars, Bembo posited an Italian literary language based on 14th-century Tuscan models, particularly Petrarca and Boccaccio (for poetry and prose respectively), writers whose language was considered "purer" and less experimental and mixed than Dante's. Significantly, by suggesting this model, Bembo was actually creating (selecting) a language which was not spoken and was not contemporary to the Florentine variety of his times.
Later that century the Accademia della Crusca was founded in Florence in "to maintain the purity of the language." The major work of the society was the compilation of A. F. Grazzini's Vocabulario, a dictionary of "pure" words first published in 1612 and later taken as a model by other European states. It was obvious by then that standard Italian was no longer a theoretical concept but a viable linguistic entity, regardless of whether or not anyone actually spoke it.
Washing His Literary Linen in the Arno
Another watershed in the evolution of standard Italian was the publication of I Promessi Sposi, an Italian historical novel written by Alessandro Manzoni and first published in 1827. Manzoni's famous quote "...lavare i panni in Arno..." referred to the influence of the Florentine vernacular on his work. He actually revised and republished the novel in the Tuscan idiom (Manzoni himself was from Milano) in a deliberate effort to provide a language that he hoped would be commonly used by most Italians.
The novel, considered a masterpiece of world literature, is a paradigm for the modern Italian language, and widely read and studied in every school. Many expressions, quotes, and names from the novel are still commonly used in Italian, such as Questo matrimonio non s'ha da fare ("This marriage is not to be performed", used ironically).
National Unification, Linguistic Unification
Not long after I Promessi Sposi was published, the various states of the Italian peninsula were unified into the single state of Italy after a series of military battles, political upheaval, and social movements. One of the platforms that motivated some of the reformists was the idea of Italian as the national language. Interestingly enough, though, only 2.5% of Italy's population could speak standard Italian when it became a unified nation in 1861. That situation changed, though, when Rome became Italy's capital. The "inflow of people from all over Italy turned the city into a linguistic lab where standard Italian became a spoken language. Just a few years later Milan joined Rome in this role because of industrialization, which recreated a situation in which immigrants flocked in and had to communicate with people from all over Italy."
(Non) Standard Italian
Given the complex route that standard Italian has taken—from la vulgata dantesca to corn flakes and crusty Florentines, from Manzoni's laundry to being declared the national language of a new nation in which almost no one spoke it—who speaks Standard Italian today? Well, almost everyone...and no one!
Today, schoolchildren from all regions of Italy learn standard Italian, and perhaps also their regional dialect. Most Italians, though, use varieties along a continuum from standard Italian to regional to local (dialect) according to what is appropriate. Their speech patterns have variations in lexis, and tend towards an intonation that is typical of the area they come from. But then, who would want to ..."speak like a dictionary or un libro stampato" or like a professional actor with a very strict phonetical diction"?