Greetings, fellow humans. I also am a normal human, like you. Definitely not an alien learning your languages to one day overthrow your species.
Is this a natural, common thing to say (like "Hi, folks!"), or is it a Duolingo-special type sentence?
Thanks! Where does it fall on the formality scale from "Hi, folks" to "Greetings, ladies and gentlemen"?
"Hi folks" or "hi people", is a popular phrase, you could use it for friends or young people for example. Your "greetings ladies and gentlemen" is much more formal for people you don't know or are older than you. It would be more polite in this case