How do you convey the feeling of being unable to speak the majority language in the area where the story is taking place?
This refers to language as a barrier to travel through shadows.
Indeed all the oldest members of the royal family can be a touch formal, as is Corwin on occasion in the Zelazny canon. They may use if particularly when feeling intense emotion.
The basic premise of my campaign and language is here. Thari is not a universal translator. Earth is not a cross-road of languages that apply throughout shadow.
Therefore a dramatic necessity of language does crop up in my stories. It allows for a bit of clever RPing from the players. I also do not allow telepathy to facilitate translation. Brains are wired to language, memory is stored by language and culture affects language as well. There is no "psyche link" to talk to those that don't speak your language.
And yes, it's fun when a royal of Amber occasionally becomes a jelly doughnut due to these constraints.