See:

http://suggesty.wmflabs.org/w/api.php?action=query&list=search&srsearch=Jesenwang%20flugplatz&srenablerewrites=1&cirrusAltLanguage=yes

And:

http://suggesty.wmflabs.org/w/index.php?search=Jesenwang+flugplatz&title=Special%3ASearch&go=Go
vs.
http://suggesty.wmflabs.org/w/index.php?search=Jesenwang+flugplatz&title=Special%3ASearch&go=Go&cirrusAltLanguage=yes

To make it easier i've flipped the configuration, cirrusAltLanguage defaults to yes, it can be disabled with cirrusAltLanguage=no. This basically means the feature is enabled if you type into the search box. We have german and russian indexes configured. The russian one isn't a complete import yet though (trying one more time..its up to 50k docs and died at 380k before). I've also put a temporary hack in place so Special:Search will generate search results for local titles that don't actually exist.

This make the links now:

http://suggesty.wmflabs.org/w/api.php?action=query&list=search&srsearch=Jesenwang%20flugplatz&srenablerewrites=1

And:

http://suggesty.wmflabs.org/w/index.php?search=Jesenwang+flugplatz&title=Special%3ASearch&go=Go&cirrusAltLanguage=no
vs.
http://suggesty.wmflabs.org/w/index.php?search=Jesenwang+flugplatz&title=Special%3ASearch&go=Go

Italian:

http://suggesty.wmflabs.org/w/index.php?title=Special%3ASearch&profile=default&search=azione+lyon+polizia

Russian:

http://suggesty.wmflabs.org/w/index.php?title=Special%3ASearch&profile=default&search=%D0%BF%D1%80%D0%BE%D1%82%D0%B8%D0%B2%D0%BE%D1%82%D0%BE%CC%81%D1%87%D0%BD%D1%8B%D0%B9+%D1%82%D0%B5%D0%BF%D0%BB%D0%BE%D0%BE%D0%B1%D0%BC%D0%B5%CC%81%D0%BD%D0%BD%D0%B8%D0%BA&fulltext=Search