It seems reasonable to me that this is not a compile time constraint, but rather one of tooling and the deployed environment- ie: is the Japanese translation available here at runtime? How? Is there a runtime configuration flag? Is the translations file available at runtime? Is the date formatter configured appropriately?

Maybe if you bake in assumptions about the deployed environment at compile time you can catch errors earlier for your specific environment, but all environments? No. That’s not the responsibility of the standard library and given the language lacks a single specific runtime target- definitely not the responsibility of the language/compiler. This is instead a classic use case for tests and opinionated (optional/third party) libraries instead.