The onboard currency for Royal Caribbean is U.S. dollars, even when in Europe. However either dollars or Euros will be fine for tipping. The casino runs on dollars too, but they'll exchange Euros. Bottom line for me is I'd have a stash of dollars just for use onboard and save my Euros for the ports.
Royal Caribbean does not have self-service laundromats on any of their ships.
I spent half of last December aboard Liberty Of The Seas, plus 4 more days this January. I previously had also sailed on Liberty on it's first revenue cruise and on the December 2011 Rock Legends cruise. So bottom line - I've spent more time on this ship than any other in their fleet. I like the Freedom class ships.
It is really just a stretched Voyager class design, which they had to do to accommodate the FlowRider and the kids water park.
The crew onboard recently was excellent with lots of European staff who were anxious for the ship to return to Europe. Nothing stands out as a 'must do' while aboard although Royal has spent a lot of money on their new shows. I liked to hit the pub in the promenade every night for a pint or two of ale. They have a fairly extensive list of beers and ales.
No need to take crash courses in French or Italian. My experience has been that people who live in those ports speak enough English that tourists can get by. Plus if you have Spanish speakers with you, Italian is close enough to Spanish that a lot of it will make sense to you.