Often a message is pre-translated into many languages, in which case a switch statement is used like this:
{{subst:#switch:{{CONTENTLANG}} |de=Hallo. |fr=Bonjour. (...) |#default=Hello. }}
(example: https://meta.wikimedia.org/w/index.php?title=Global_message_delivery%2FSpam&diff=5668882&oldid=5668677 )
This is tedious. There should be a way to do this without writing out a huge switch statement.
URL: http://lists.wikimedia.org/pipermail/translators-l/2014-February/thread.html#2482