You should always expect some language barrier when traveling abroad to a place where English is not an official language. My guess is that a Disney veteran won't have that much in the way of complicated questions to ask. But if you do, expect that question to elicitt some confused stares. For example, at TDS there is a readly available map of the Fortress Exploration in Japanese, but if you want one in English (makes a great souvenit, BTW), then that might take some time. Also, the activities are not really explained in English, so good luck in figuring those out. The staff was of little help, I'm afraid.
Imagine, for example, how confusing FP is at WDW or DL. Even for an English speaker. A newbie to either place could easily become confused.
You should pick up some language skills. Nothing complicated. Just peruse a P\pocket translation guide on the plane ride over. Figure out how to say excuse me (very helpful in crowded places) please, thank you, where are the bathrooms... figure out how to say "I'd like the front row please" in Japanese before riding Journey to the Center fo the Earth. Makes a difference! You could learn all that in just a few minutes on the plane ride in Japanese.
Chinese is harder because of the pronunciation. Even then, a few simple phrases will go a long way.