[eluser]xwero[/eluser]
You need to url encode the pipes symbol : %7C. I guess the query string will also have to be url encoded, to be on the safe side.
It's not a real solution because further tests i did with other urls made me aware of the fact that the language of single segment urls quite often doesn't get recognized.
Another dealbreaker is that the actual controller and method name has to be what the translate api provides you. So you can only use it with controllers/methods you are in control of. Or you need to run the slugs through google translate as well.