I think we call a pull-over jumper a jumper whereas one with a zip would be a jacket. "American" words that are like knives to my ears are candy, garbage, and could care less. We distinguish lollies and chocolate, we dump rubbish, and we couldn't care less. "Didn't do nothing" always bothered me too because it's a double negative. If you didn't do nothing, that means you explicitly did something.