Here is an extract from the film "My Fair Lady" so you can learn how to pronounce and understand different accents...
It is a musical about Professor Henry Higgins, who takes a bet from Colonel Pickering that he can transform unrefined, dirty Cockney flower girl Eliza Doolittle into a lady, and fool everyone into thinking she really is one, too! He does, and thus young aristocrat Freddy Eynsford-Hill falls madly in love with her. But when Higgins takes all the credit and forgets to acknowledge her efforts, Eliza angrily leaves him for Freddy, and suddenly Higgins realizes he's grown accustomed to her face and can't really live without it.
And here is a funny video about a boy attempting to do 24 different accents from his own country and from other countries around the world... careful, because you'll sometimes hear some bad words (sorry for the inconvenience...)
Listen and try to recognize the different accents...
And to show you how important it is to understand English... watch this very funny video:
And here, you can listen to the difference between the British and the American accent:
And here is an interesting link to practice your oral comprehension: