[throwvondannen]

I'd love to hear Lojban in a mainstream movie. https://en.wikipedia.org/wiki/Lojban

Bonus points if it's sold as random fantasy language of a strange country and the main cast doesn't understand it either.

[fusiongyro]

Lojban is so big, you could create different cultures simply by omitting or making mandatory different bits. This group doesn't use rafsi but evidentials are mandatory; that group doesn't use any of the time-space marking but the other does, etc.

[mccosmos]

Not quite a movie but having Lojban as the setting fantasy language is the idea behind this new production: https://www.youtube.com/watch?v=4kJATTd6vF8