My humbled opinion ... concentrate on studying for the CPL until you have it in your pocket, if you want to be a professional helicopter pilot. Get a distance learning course and study everything up to ATP/IFR level. That will keep you busy for a while and increase your chances of finding a job as a helicopter pilot. If you want to fly offshore, know as much as you can about IFR rules, get a flight manual for one of the types they fly and study it and maybe even try to get your hands on their SOP's and COM's. Knowing your stuff is how you can really impress your colleagues or a Chief Pilot during a job interview. A CRM or MCC course is also very good to have, if you want to get into the multi-crew environment.
Offshore operators will put you through all the other courses that you are required to have. For example Dangerous Goods, Underwater Egress, First Aid and H2S.
If you are really smart and disciplined, you could get a bachelor or masters degree related to aviation in conjunction with your ATP and advance into a management position, once you have enough of flying.
If you are more interested in seeing where you are going, you could learn about mountain flying and vertical reference flying. Being well versed with basic aviation stuff still applies here as well. And lets say the company you want to work for is flying AS350's, then that's the flight manual you should be studying before the job interview.
Learning a language and stuff like that is fantastic and very desirable for your personal development, but I think in most cases it would not increase your chances of getting a job as a pilot.
Good luck!