let see:
the idea of rokugany dialets and language is something I can see, I can imagine indeed a high rokugani inspired and use by the crane to the point it just become the point were "high speech" being asociated to "whatever the crane said it is" one of those thing that is drive by cultura inertia as all thing rokugani are.
The scorpion would have a secret language of codes they usually keep update every so and then in a way to talk with another in situation they know they have being spy on. In short, spy-talk
Mantis and unicorn clearly speak forein words between themselves when they can indulge, something they dont with the rest of the land for obvious reasons.
Shadowlands have is own language, the spider know it and knowing it means death.....but also because how close they are, it means the crab probably know it more than anyone. everyone just ignore it
