Languages can literally die overnight when the last of their speakers dies, but the death of Latin was very different.
After the fall of the Roman empire in the west in AD 476, Latin evolved into a wide variety of regional dialects now known as Romance vernaculars. In the early 14th century the Florentine poet Dante Alighieri reckoned that more than 1,000 such dialects were spoken in Italy. At the time of Dante, Latin was still used in literature, philosophy, medicine and other cultural or legal written documents. Dialects were spoken, but also used in writing: the earliest examples of vernacular writing in Italy date from the ninth century.
The early 16th century saw the dialect used by Dante in his work replace Latin as the language of culture. We can thus say that modern Italian descends from 14th-century literary Florentine. Italy did not become a single nation until 1861, at which time less than 10 per cent of its citizens spoke the national language, Italian.
Throughout the first half of the 20th century, Italy was a ‘diglossic country’ – one where a local dialect such as Neapolitan or Milanese was spoken at home while Italian was learned at school and used for official purposes.
The First World War helped foster linguistic unification when, for the first time, soldiers from all over Italy met and talked to each other. The rise in literacy levels after the Second World War and the spread of mass media changed Italy into a bilingual nation, where Italian, increasingly the mother tongue of all Italians, coexists and interacts with the dialects of Italy.
Answered by Delia Bentley, senior lecturer at the University of Manchester.