What is the difference between a Latin word root and a Greek word root?

Answer 1

To answer the latter part of your question: Why do we use them in English. Well... It has a lot to do with the Roman Republic and Christianity. Greece was a highly cultured civilization, albeit one with little geographic control outisde of its two oceans. Still, Greek thinking was very advanced, and spread around the Mediterenean sea. When Roman and Greek culture clashed, Rome ultimately won control, but Rome always had a 'soft spot' in its heart for Greek culture and Greek language. Wealthy Romans without exception were taught to read and write in Greek, and were taught Greek philosophy.

Now, enter Christianity. Christianity began to flourish in areas dominated by the Greek language at least in writing. This would be the regions of Greece, Turkey, and Syria as we know them today. Greek language helped keep Christian writings in circulation for quite a long time.

Eventually the central hub of Christianity became Rome itself, no doubt because one of the early writers in Christian theology, St. Paul, was a Roman citizen, and enjoyed the benefits of free travel throughout the Roman Empire. Obviously he would have been fluent in both Latin and Greek.

Ultimately, the Greek Orthodox church and the Catholic Church split, each using its own language to keep record of church teachings. Greek influence wanes as the Dark Ages take over Europe. But Latin remains strong throughout Europe and the near East, and indeed, the Catholic Church, based in Rome and in Latin, is one of the best unifying forces for Europe throughout the Dark Ages (which isn't saying much, but the Latin language was THE language of writing for hundreds of years).

As the enlightenment grew out of the Dark Ages, Latin grew in importance as a symbol of erudition, and Greek as well. The Greeks had begun many of the scientific schools of thought, whereas the Romans typically received more credit for having organized political institutions. To this day, Greek references are more common in sciences and Latin are more common in legal and political.

Ultimately they stayed relevant because knowing these languages was a sign of intelligence in history, science, and literature.