What that means is, the client works in whatever language you want it to, regardless of which server you’re connecting to. Effectively this can mean that three players could player together in English, French and German at the same time, while connecting to a server that is labelled as US-English, for example.
The point is, you won’t be forced into playing in a certain language, but you will be informed what the expected/suggested language of the server is when you connect to it.
Before you ask – no decision yet on whether servers will be labelled with languages other than our three officially supported ones (English/French/German). I’m sure the community will unofficially label servers themselves, though.”