This person is very rude and believes he/she knows everything about the world, especially North America, when in fact he/she does not know anything.
These people are always in other peoples business and mad about everything they believe to be "incorrect".
It is common for this person to mispronounce words and act like their pronunciation is more correct than any other.
A "know nothing, know it all".
*Note: Not all British people are Snobs, but the Snobs out there are usually British.
British Snob: No, no! It's Oestrogen...
Average person: Not in America.