In Germany it's not common to have cons going on until Monday. Let's put it bluntly: after the BigBlueDance Saturday night* the con is over.
There will still be a lot of folks around on Sunday, and there's some DeadDog event happening in the evening, but basically everything which is Eurofurence - the panels, the stage, the artshow, the den, the decoration - will be gone and disassembled.
*) At least it's "German Night", i.e. can easily be 5am on Sunday.
As for Wednesday, there is the opening ceremony in the evening. Programming is Thursday to Saturday. Staff and way too many other folks will be around starting Tuesday, so even before the con officially opens there will be lots of social gathering and fursuiting.
English is the official language of Eurofurence, so everything will be in English. You can thus also assume that all attendees are good enough in English for communication :)
*purrr*