There are many difference's between American and British English! If someone know's English they'll be able to navigate an English speaking country, but there are some differences such as: Idioms Pronunciation Spelling (famously color vs colour) Phrasing and even some vocabulary and punctuation! Here's some examples: American English Color Dialog Aging Center Trunk Cookie British English Colour Dialogue Ageing Centre Boot Biscuit Those are just some of the more well known examples on how our language can differ from spelling to vocabulary. The easiest way to tell the difference is to listen to native speakers, like you are through television and film. If you're into comedy I recommend Are You Being Served or Fawlty Tower's for something to watch, both are British tv series from around the 70's and earlier. There's also the super famous Doctor Who which has been running since dinosaurs walked the Earth. I am not a huge fan of Doctor Who myself but my favorite season is with the 4th Doctor (Tom Baker). I was a big fan of Katherine Tate, a famous British comedian who had a season with the 10th Doctor (David Tennant).

I highly recommend you to watch this YouTube video. BRITISH V.S. AMERICAN ACCENTS! <https://www.youtube.com/watch?v=Ua7nyAaf3pE>; This is very interesting and funny. And you like this, there are tons of video like this on YouTube, so you should check those out :)