@rferran - the reason ca_ES just showed up as "ca_ES" in the language preferences list is because there was no code to convert that to Catalan - Spain. "ca" was in the code as Catalan so it shows up ok. I've noticed a couple new translation entries and have added code to convert them to their names as well. Unfortunately it can take a release to catch up with additions, but all the non-country specific names should be there already.
@theducks - I did add the info on how to get dictionaries to the User Guide, but I know its not always seen. I'd hesitate to put a link like that because what sites would you list and be sure they work ok.