Not only does Siri not do translations, the command / control functions that she is supposed to do, are extremely limited. Siri, at least for me, fails to work most of the time even for the incredibly simple tasks that I have tried, such as calling contacts and playing certain songs.
For example, Siri can set the alarm for 6:00am, but if I want that alarm to be set for every weekday, that task is too complex for her.
Siri can play songs, provided that your song list is filled with popular songs in english by artists with English sounding names, but if you are using Siri in English and happen to have songs in German by German artist, then Siri is useless. Ditto for making calls to contacts whose names aren't common names for the language you are using Siri in.
Siri actually doesn't seem to be much better than IBMs voice recognition software that I used nearly 20 years ago.
I can't see why anyone is remotely impressed with Siri, it is just a useless waste of time as far as I can tell. Google translate, on the other hand seems really impressive with being able to recognize the speech and translate it to another language.