Latin was the Language of the Romans, not sure why Chazal would say they didnt have a language
While I dont know where the Latin Alphabet comes from, I can tell you from my travells Its alot easier going to a country with a Latin Alphabet than going to one without it. Even if I cant pronounce any of the words, I can read the street signs easily. Having an Alphabet that nobody else uses is a problem in todays global world.
The exact number of words in any language is impossible to count, as some languages allow compond words with grammar and english allows alot of latin scientific words