As a native English-speaker living in a country with a tonal language, there are innumerable opportunities for misunderstanding, even with locals who speak pretty good English.
Small mistakes like, "We came here on a car" are easy to correctly understand. This does bring up, at least to me, the question of why is it we travel "in" a car, but "on" a bus when we are actually inside (in most cases) both of them?
One of the great opportunities I have for misunderstanding with many Vietnamese who speak English presents when I ask them a question in the negative. For example, "Are you sure you don't want to go?" Most Westerners answer "Yes" (I'm sure).
Every English-speaking Vietnamese I know answers, "No" (I don't want to go).
After almost four years here, I still have to pause after asking such a question to think about how their "yes" is my "no" and respond correctly. Most often, I immediately ask the question again in a different way: "You don't want to go?" which gives me a "Yes" (I don't want to go) and frequently a look questioning why I asked again. Somehow, this makes more sense to me: "Yes, I don't want to go." We westerners, would of course, answer, "No, I don't want to go."
Re-wiring my brain to "get it" on the first try is going to take a bit longer.