Foreign Students

Don't take any of this to mean that I have problems with students that aren't American. I actually respect all of them. Going to a different country to study for a year or more is amazing. Especially when it is a county with a very different culture and one that speaks a different language.
However, I was just noticing something and felt like sharing it with everyone. It seems like the students that come from Africa are always the most polite, and have the best grasp of the English language. Of course, the second one doesn't apply to students from England. There was just an African student in the office for some assistance. He was incredibly well spoken and I only occassionally had trouble with his accent. And that was only when he got a little excited. He started talking a little faster and didn't control his accent quite so much. It got a little bit thick for my poor ears. But he spoke so well, and he was very nice. I wish all the exchange students that came through were like that. However, a lot of them have trouble with English, and a lot of them are a bit rude.
Even foreign professors that come and live over here for years aren't as polite, or have such a grasp of the English language, as this kid was. I wonder if it is a cultural thing.....