Shakira,
I must agree with you that not everyone speaks perfect english. But how would that matter with CRM? In case of emergencies, would it be that they cannot express what is wrong?
I also know of cadet pilots that do not speak well english either. What is the sense in that? Point being is that if they can get the job done, wherebeit flying the aircraft or serving the pax, then that is what counts.
Perhaps there is something you don't know how to express in your question....