The society here was really interesting with its hyperfluid language--was that based on an actual culture or was that entirely fantastical, does anyone know?
Yes
I think it's us. As I listened to this I couldn't help but think about the mass extinctions and changes in human languages. Whether it's by deliberate annihilation such as the extinction of the Arawak on the arrival of Columbus In the Bahamas, or the more passive cultural assimilation that has swallowed languages for eons.
English itself is after all a highly fluid "bastard" language that has swallowed large parts of both its captors (the french gave us most of our legal terms during the Norman conquest. Also the Romans, Vikings etc) or our captives (words like shampoo and umbrella are from india).
Mass media has accelerated this process , and the Internet - the mother load of all media - has put incredible pressure on both rare indigenous languages, and the dominant languages, which are possibly changing faster than ever. I listened to a BBC Radio documentary a while ago about how English dialects are disappearing amongst the youth as they adopt a form of amalgamated "London speak". Unfortunately , I can't remember the title of that podcast, so if anyone else knows anything about that, I'd love to revisit it.