This makes me wonder is a there a programming language which has separate data types for locale aware and locale independent strings. I know that rust has OsStr

This makes me wonder is a there a programming language which has separate data types for locale aware and locale independent strings. I know that rust has OsString but that's a slightly different usecase. Problem with the current widely used approach of having global application wide locale setting is that most applications contain mix of User facing strings and technical code interacting with file formats or remote APIs. Doesn't matter if you set it to current language (or just let operating system set it) or force it to language independent locale, sooner or later something is going to break. If you are lucky a programming language might provide some locale independent string functions, but using them is often clunky and and unlikely to be done consistently across whole code base and all the third party libraries. It's easier to do things correctly if you are forced to declare the intention from the start and any mixing of different context requires an explicit conversion.