Dialects are linguistic varieties which differ in pronunciation, vocabulary and grammar from each other and from the standard language. British linguists distinguish dialect from accent, which refers only to pronunciation.
In the United Kingdom much emphasis is placed on Received Pronunciation, an educated dialect of South East England. General American, which is spread over most of the United States and much of Canada, is more typically the model for the American continents.
American English is a set of dialects of the English language used mostly in the United States. In certain respects, American English is closer to the English of Shakespeare than modern British English is. (e.g., fall as a synonym for autumn, trash for rubbish) American English and British English differ at the levels of phonology, phonetics, vocabulary, and, to a lesser extent, grammar and orthography.
Because English is so widely spoken, it has often been referred to as a "world language", the lingua franca of the modern era, and while it is not an official language in most countries, it is currently the language most often taught as a foreign language.
A lingua franca is a language systematically used to make communication possible between people not sharing a mother tongue, in particular when it is a third language, distinct from both mother tongues.
Following the economic, political, military, scientific, cultural, and colonial influence of Great Britain and the United Kingdom from the 18th century, via the British Empire, and of the United States since the mid-20th century, English has been widely dispersed around the world, become the leading language of international discourse, and has acquired use as lingua franca in many regions.
It is strange that a language that started on a small island 1500 years ago as the result of the invasion of a few Germanic tribes is the international language it is today.
Approximately 375 million people speak English as their first language. One out of five of the worlds population speaks English to some level of competence. Demand from the other four fifths is increasing It is widely learned as a second language and used as an official language of the European Union and many Commonwealth countries, as well as in many world organizations.