Hoi,
When you show a text that is not of the language you make it hard to understand what it means. I hear you when you have a problem with caching but do you realise what problems you introduce when you show information that is not of that language?
In my opinion you can cache everything that is of that language and show what is in a different language in a different colour. It would be better to show the information that is in a different language according to the #babel information and when there is nothing in any of those language just show something.
I may be confusing.. In the major languages it is a problem that sorts itself out, in the smaller languages it is vital to show information that makes to the people that read the data. Consider for instance people that emigrated to all parts of the world. It is the only sensible way (not for computers but for people).
Thanks,
GerardM