English is a West Germanic language originating in England, and the first language for most people in Australia, Canada, the Commonwealth Caribbean, Ireland, New Zealand, the United Kingdom and the United States. It is used extensively as a second language and as an official language throughout the world, especially in Commonwealth countries such as India, Pakistan and South Africa, and in many international organisations.

Modern English is sometimes described as the global lingua franca. English is the dominant international language in communications, science, business, aviation, entertainment and diplomacy. The influence of the British Empire is the primary reason for the initial spread of the language far beyond the British Isles. Following World War II, the growing economic and cultural influence of the United States has significantly accelerated the spread of the language.

Because a working knowledge of English is required in certain fields, professions, and occupations, English is studied and spoken by up to a billion people around the world, to at least a basic level (see English language learning and teaching). English is one of six official working languages of the United Nations.

Source: http://en.wikipedia.org/wiki/English_language