You would be surprised. At a previous job, we would receive guests from all around the world, and particularly from African, Asian, South American, and 2nd-tier European countries. The Africans and SEAs were by far the most consistently, fluently conversant. The (comparatively wealthier) Eastern Europeans and East Asians seemed to understand written English most proficiently, but seemed to loathe speaking it; the former broke the "English only" classroom rule most often.

Edit: I'm not surprised by the downvote, simply bemused.