RP and General American

Today, when English is one of the mahor languages in the world, it requires an effort of imagination to realize that this is a relatively recent thing - that in Shakespeare's time, for example, only a few million of people spoke English, and the language was not thought to be very important by the other nations of Europe, and was unknown to the rest of the world.
English has become a world language because of its establishment as a mother tongue outside England, in all the continents of the world. This exporting of English began in the seventeenth century, with the first settlements in North America. Above all, it is the great growth of population in the United States, assisted by massive immigration in the nineteenth and twentieth centuries, that has given the English language its present standing in the world.
People who speak English fall ito one of three groups: those who have learned it as their native language; those who have learned it as a second language in a society that is mainly bilingual; and those who who are forced to use it for a practical purpose - administrative, professional or educational. One person in seven of the world's entire population belongs to one of these three groups. Incredibly enough, 75% of the world's mail and 60% of the world's telephone calls are in English.

The topic I have chosen is very interesting, I suppose. It is about the difference between British and American English. This topic was the only one I paid my attention on from the very beginning. I study this language at school for 10 years. English is an international language spoken in the countries all around the world. Of course, it is very important to speak English and all other languages right. English is different in Great Britain and America, Ireland an Scotland. And I am interested in this difference. I thought English is similar in different countries. Well, it is, but it is as similar as different! What do I mean? My father always speaks English on his work. Once he has been to America and spoke to a man. And during their conversation they didn't understand each other almost. My father said : "That man spoke american, not English." He saw my surprise and explained me that people speak different in America. So I will try to find this difference and find the reason why does it happen.