Comment 12 for bug 48708

reopening.

I may well want to read a Japanese or Chinese PDF from time to time. That doesn't necessarily mean I have the language-pack installed. I'm sure we can do better than the current situation.

FWIW, acroread detects when there are glyphs in a PDF that it cannot properly display currently. Maybe that's a different option. I understand both approaches have drawbacks. I can't immediately present the most appropriate solution.