Why just the featured story? I see you use - at least partially - the original multilingual hack by Euan.
Euan's code is outdated and was later fixed and improved by yours truly - especially since Euan's version stopped working once Geeklog was upgraded. My code's purpose is to achieve the same thing, but while interfering as less as possible with Geeklog's core.
If you use it, your visitors could choose a language (via a cookie) and will only see topics and stories (and in my new version, also polls) in that language.
I've kept my hack updated in the "feature request" sub-site, which is down currently.
And I don't know where else to keep this code, so I've just opened a new topic just for my own hack
. I would always keep it updated there from now on.