To apply you just need to go to  here and follow the steps.

And its like any other job in the entertainment industry to become part of Disney’s entertainment cast. Applications, auditions, and just luck that when you audition they are looking for a role you fit into. I know of quiet a few tumblrs out there in the Verse that work or have worked in entertainment. if you make the effort to find them i bet they would be willing to give you more information about the audition process and all that jazz!

As for Disney Parks out of the USA I can not give you an answer. but I feel you would have to know a little at least when working in entertainment and a full grasp on the language when working anywhere else with guest interaction. 

and thank you very much! we always like to hear that we are doing a good job.