Like most Americans, I left the States thinking I had no accent. As soon as I arrived, though, I became starkly aware of my American twang. I could suddenly pick other Americans out across the room by their accents, and I became conscious of trying to make my vowels sound less American. I found the Northern English accent more difficult to understand, but the feeling was mutual in one instance. Food was always a challenge.
Herbs are herbs, but with the h pronounced.
I first learned this at a student grocery store from a sign that was clearly put up for clueless Americans. Sandwiches are a whole other ballpark. Tomato isn't a topping, but a filling. Schoolwork produced its own words. We might have 15 hours of class a week, while a social science or humanities student in Britain could have as little as four hours total.