In classical antiquity, Europe’s major written languages were Latin and Greek. Why is it that the former is long extinct, while the latter is still spoken?
In point of fact, neither has died, but both have changed. That’s normal, given that natural languages never remain constant very long. Over the centuries, Latin has acquired new names, whereas Greek hasn’t.
Modern Greek resembles its classical predecessor, but the differences are substantial. When today’s Greeks try to read Homer’s or Sophocles’ writings, they find it’s mostly Greek to them – or rather, it isn’t. Latin has also changed a great deal, but unlike Greek, it has done so in very different ways from one region to the next. You might say that each of the Romance languages, such as French, Portuguese and Italian, is the ‘Modern Latin’ of its own region. As with Greek, classical Latin is largely unintelligible to speakers of the modern varieties. A modern Roman can’t read Caesar.
The real contrast between Latin and Greek then is that while Latin has gone to pieces, Greek has by and large maintained its unity. How is that to be explained?
In the Late Middle Ages, Latin-speaking Western Europe saw the rise of separate states, each of which developed its own standard language, such as French and Portuguese. The Greek-speaking areas of South Eastern Europe, on the other hand, were almost uninterruptedly part of a single (albeit multilingual) empire, first Byzantine, then Ottoman. Moreover, the Greek Orthodox Church provided a strong unifying force. So it was both politics and religion that stopped the language going Latin’s way.
The above is my answer – translated and somewhat expanded – to a reader’s question in the Dutch popular-science magazine KIJK.