Does the toolserver have this functionality or should always complete translations be made?
As far as I know, it has fallback to English (no multi-leveled fallback chains).
Thank you for your reply. Thus all translations should be complete, e.g. de-formal, de-ch, etc. It just seems to be a question of necessity.
The Intuition project has had support for fallback languages since the beginning.
It has current language -> (if available: fallback lanuage ->) English.
However the fallback system is not as complete as MediaWiki's. Currently there are 13 fallbacks defined.
They can be found here
Sounds like you might want to write a little PHP script to extract the fallback configuration from MediaWiki to make this work. Shouldn't be too hard... Grep "$fallback" on phase3/languages/messages/Messages*.php.