Indeed, nothing outside that range can be properly handled by the parser. This is a significant problem when trying to write IF in different languages, since the limited range shown above isn’t even enough for the entire European Union. (Greek, for instance, is missing its entire alphabet, while other languages have more subtle problems: Polish needs letters like ż, Romanian ă, Icelandic ð…it looks like you’re specifically missing Hungarian’s ő?)
Zarf has written an extension that updates the parser to support Unicode. But since you can’t use most Unicode characters in object names or Understand lines, you need to use Inform 6 inclusions for all parsing-related code (Understand lines, object names, verb definitions, conversation topics…).
Hopefully an upcoming release of Inform 7 will change this. But for now, it’s not really possible to use it for works in most non-English languages. Sorry about that.