Thomas Shey
Legend
Most campaigns don't tend to travel very far - look at the official campaigns, mostly all set on the Sword Coast. Having Chult speak an unintelligible language for the most part might have helped differentiate the people there from Sword Coast-ites.
All of this is easily ignorable for people who just want a combat sim, just as I suspect they ignore the current half-arsed system.
That was a little unnecessary. People can want a lot more than a combat sim but still not consider language differentiation interesting to deal with except in the most casual way.