I know that I tend to find little features months after they are talked about, but I was just doing a define: in Google and it seems to have translations mixed in now. The only languages available at this point were Chinese (Simplified) and Chinese (Traditional)
http://trex005.googlepages.com/define_languages.png

I saw this before, but can't tell you how new/ old it is...
I only came across it accidentally too...

Philipp you're right, it's pretty old (months/years ago)