They don't. Some Science Fiction writers and film producers have been of UK origin: H.G. Wells, Arthur C. Clark, Gerry Anderson, that might explain it. I think you are probably thinking of the Alien mad scientist (Exeter) from the movie "This Island Earth". It is merely a facade of culture. This is certainly not true of all media space-alien portrayals.
If the nun is British, she probably will have a British accent. If she's German, she'll probably have a German accent.
No one speaks British. They have a British accent.
Yes.
I can hear a distinct British accent when you speak.
yes, he has a british accent.
Overall, people in Brazil do not have a British accent. The official language in Brazil is Portuguese, and thus the majority of people speak with a Portuguese accent. However, due to global influences, some Brazilians may speak English with a British accent if they have been exposed to that dialect.
Yes, if you mean English. British does not exist. She does have a British accent also
No, he is Australian, so he has an Austrailian accent. He does speak French, though.
There is actually no such thing as a British accent. There is an English accent, a Scottish accent, an Irish accent, or a Welsh accent. These are generally spoken within their own countries (English in England, Scottish in Scotland, etc.). However, people all over the world may have a breed of a British accent because either they are immigrants themselves or they picked it up from their family.
There is no such thing as a 'British' accent. The accent commonly heard in Harry Potter is the ENGLISH accent. I can see no reason why anyone would stop you from auditioning for a part.
Rihanna is from Barbados and speaks with a Bajan accent, which is a variant of Caribbean English.
Most people speak with accents, and pirates are just people.