I hope for you, since it is the Western Med (close to the British Isles) that they will have plenty of English-speaking tours. if you can, get on a tour with English only - when they are bilingual sometimes the English gets less attention.
One advantage, however, is that many Europeans who do not speak any of the Roman languages do speak English, so they often go on English speaking tours (making them less likely to be cancelled).
Mallorca is wonderful - but make sure you just take a taxi to the Cathedral - it is only about 5 Euro. I had a very hard time getting a taxi back to the ship however, so plan on either leavong early or later, but not at rush hour (it is a surprisingly populated island).
If you must, you can walk betwen the ship and the shopping district, but it is about 1 1/2 miles.
Barcelona - it is very easy to walk to Las Ramblas from the ship (about a 20 minute walk) now that they have built a new bridge to the port area - or take a taxi. Once you reach Las Ramblas from the water, head inland and just look for interesting streets. There is MacDonalds along the way - turn right around there and you will find tons of great shopping and sight seeing.
It is also worth a short tour to see the Gaudi architecture. But don't spend all day on a tour - save some time for walking around on your own.
If you are very adventurous, the Metro (subway) can be VERY handy for helping you get around, but I did not find it that easy to navigate locally. You need a map and directions on what to do.