I often hear it said that the average people under the Roman Empire did not speak proper Latin but rather Vulgar Latin, which dispersed throughout the empire and became the numerous Romance languages we have today. Sure, that's fine and good. But where did Latin come from?
Surely Latin did not start off as being a stuffy, bookish language. Who was speaking Latin while the nobility was using Greek? What were the soiled farmers, prostitutes, and wretches speaking? Were they going around saying "Roma invicta" at some point? How did this form of Latin come to take the high seat during the Classical era?
I understand this question is complicated but I just wanted some insights into the origins of Latin. It is my understanding that languages generally start with the common folk, but I can't seem to figure out who the common folk were that led to the language used in high texts.
I can recommend some earlier answers which may clear things up.
To start from the beginning, Latin was an Italic language native to Latium, the area in whose northern end Rome is, which you can read about in this thread by u/QVCatullus and this by u/XenophonTheAthenian.
There was also never a time when the nobility exclusively spoke Greek. As can be seen from the quotes u/Misticsan includes in this thread, some Roman elites (notably Cato the Elder) were quite sceptical to Hellenic culture and the language when the Romans came into major contact with Greeks. It was taught as a second language to the children of the elite, as u/KiwiHellenist has written about here, u/amayo20 here, and u/UndercoverClassicist here. And from the examples u/toldinstone provides here, you can see that Greek was not uniformly associated with the upper class either, due to immigration from the Greek east. When it comes to the difference between Vulgar and Classical Latin, I can recommend this older thread by u/XenophonTheAthenian. There was never one Vulgar Latin, just like there is not one "slang/informal English" today
For a general summary of the Latin language and how/when it was used one can also read this blog post by u/Spencer_A_McDaniel. I hope this is helpful!
Classical Latin WAS spoken Latin. It was the Latin the upper class Romans in Rome spoke. The idea that "Vulgar" Latin and written Latin were different languages is absurd. Later on the languages became different, but they were the same and similar very early on. Before Classical Latin there was Old Latin which would be your "Pre-Classical" Vulgar Latin I guess.