English is a Germanic language, as opposed to the Latin-based
Romance Languages like Spanish, French, Italian, Portuguese, etc. If you look at modern English and compare it to any of the
Scandinavian languages you will see many similarities. The reason English has Latin roots as well is because of French influence: in 1066 A.D. the French defeated the British at the
Battle of Hastings. The British are still pissed about that one.
After the Battle of Hastings, the French became the elite ruling class in Britain. Of course common people idolize what they see in high society, so french culture became the new standard for the masses to mimic. This permanently entrenched french culture in Britain.
Many English words come from Latin via French, but thanks to the melting pot nature of America, many more words were added from all different cultures. Anyway, because of the French, there are two ways to say nearly everything in English, a latin-based word and an old-german based word. (example: Drink==German, Imbibe==Latin)
**A note about Greek word origins: during the time of the expansion of the Roman Empire the Romans conquered Greece. The Romans, however, were not your average pillagers, and instead of wiping out Greek culture and replacing it with their own, they saw the brilliance of Greek thinking, innovation, and advancement. The ancient Greeks were very scholarly, having already done much research into the sciences and making many discoveries, as well as the profound Greek philosphers and artists. Romans hailed Greek culture, and brought it back to Rome. This is why you'll see much Greek influence in later Roman architecture, and why nearly all of our scientific words have Greek origins.