I don't think uppercase/lowercase is an issue and in fact it is something that already happens. For example in most languages lowercase "i" has the letter "I" a

I don't think uppercase/lowercase is an issue and in fact it is something that already happens. For example in most languages lowercase "i" has the letter "I" as uppercase version, but not in Turkish, where it gets converted to "İ" (with the dot). In Turkish "I" is the uppercase version of "ı" (without the dot). In other words the same letter can be "uppercased" to a different letter depending on the current language