“The first occasion on which the world of medieval Christianity had to confront a systematic project for a perfect language was De vulgari eloquentia (hereafter DVE) of Dante Alighieri, written presumably between 1301 and 1305.
Dante’s text opens with an observation which, obvious thought it may be, is still fundamental for us: there is a multitude of vulgar tongues, all of them are natural languages, and all are opposed to Latin–which is a universal but artificial grammar.
Before the blasphemy of Babel, humanity had known but one language, a perfect language, a language spoken by Adam with God and by his posterity. The plurality of tongues arose as the consequence of the confusio linguarum.
Revealing a knowledge of comparative linguistics exceptional for his time, Dante sought to demonstrate how this fragmentation had actually taken place. The division of the languages born from the confusion, he argued, had proceeded in three stages.
First he showed how languages split up into the various zones of the world; then, using the vernacular word for yes as his measuring rod, he showed how languages (within what we today call the Romance area) had further split into the oc, oil and sì groups.
Finally, within this last subdivision, Dante showed how particular languages were even further fragmented into a welter of local dialects, some of which might, as in Bologna, even vary from one part of a city to another.
All of these divisions had occurred, Dante observed, because the human being is–by custom, by habit, by language, and according to differences in time and space–a changeable animal.
If the aim of his project was to discover one language more decorous and illustrious than the others, Dante had to take each of the various vernaculars in turn and subject it to a severe critical analysis.
Examining the work of the best Italian poets, and assuming that each in his own way had always gone beyond his local dialect, Dante thought to create a vernacular (volgare) that might be more illustre (illustrious, in the sense of “shining with light”), cardinale (useful as a guiding rule or cardine), regale (worthy of being spoken in the royal palace of the national king–if the Italians were ever to obtain one), and curiale (worthy to be a language of government, of courts of law, and of wisdom).
Such a vernacular belonged to every city in Italy, yet to none. It existed only as an ideal form, approached by the best poets, and it was according to this ideal form that all the vulgar dialects needed to be judged.
The second, and uncompleted, part of DVE sketches out the rules of composition for the one and only vernacular to which the term illustrious might truly apply–the poetic language of which Dante considered himself to be the founder.
Opposing this language to all other languages of the confusion, Dante proclaimed it as the one which had restored that primordial affinity between words and objects which had been the hallmark of the language of Adam.”
Umberto Eco, The Search for the Perfect Language, translated by James Fentress, Blackwell. Oxford, 1995, pp. 34-5.