I get that in pop culture, Latin sounds mysterious and ancient, but demons were ancient by the time folks were speaking Latin. It sounds like I'm nitpicking, but my point is that it's kinda funny when you think about it.
The whole concept that demons speak Latin implies that Hell universally chose to learn a new human language between around 600 BC and 700 AD only spoken in Europe, North Africa, and West Asia, (completely ignoring every other civilization on Earth), and that also implies that, despite somehow successfully becoming almost universally fluent and literate in Latin, Hell couldn't be bothered to pick up another textbook for the following 1300 and some-odd years till today.