Well, mixing tiny bits of another language is already done on the server - such as the Kusarians greeting each other with "Konnichiwa", the Outcasts/Corsairs letting out a short "Hola" and the Rheinlanders giving their firm "Guten Tag".
If it's only one or two words that about anyone can understand - be it due to the context or because the translation is obvious or well-known - it is okay.
However, posting entire sentences in another languages is, as Laowai pointed out, against the rules.
What would you do, for example, if your character needs to say a lot - and it doesn't fit into the two lines the chat window offers you - you'd have to post the translation after the untranslated part. But in the meantime, the untranslated part would hover in system chat and people would probably be quite confused.
Maybe chat like this:
"Translator: Yadda Yadda (in English)"
That way, you signalize that what the others here doesn't come directly from your character - and you're within the rules.
![[Image: GhostSleip.png]](http://i281.photobucket.com/albums/kk206/gabelzahnmoos/My%20Signatures/GhostSleip.png)