I experimentally did the German translation once. The (potential) problem is that translations use differently long words. The words per line and their order is fixed. On top of that, there may be idiosyncrasies of languages so there are more (or less) words than “quarter to/past”, or we need a different order etc.
This would be the German version as is:
As you can see, the “fünf Minuten vor” looks quite cramped.
I suppose we could start collecting translations and hope someone improves the code. We could already use those translations for the languages that look OK as is.
[Edit: I added this as an issue to WordClock.]