English is English!
However, different regions can often use the language in slightly different ways, and speak it, the language, in different accents.
Don't be worried, just speak what you know, and the local people will help you!
One important accent that is not on the map is 'BBC English', or 'posh English'. All BBC presenters used to speak in an accent called 'Received Pronunciation' or RP. This sounded like the accent used by 'posh' or upper class people in England.
Nowadays the BBC language rule has been relaxed. Different regional accents can be used on BBC broadcasts.
