English is an Indo-European, West Germanic language originating in England, and is the first language for most people in the United States, the United Kingdom, Canada, Australia, New Zealand, Ireland, and the Anglophone Caribbean. It is used extensively as a second language and as an official language throughout the world, especially in Commonwealth countries and in many international organizations.
Modern English, sometimes described as the first global lingua franca, is the dominant international language in communications, science, business, aviation, entertainment, radio and diplomacy. The initial reason for its enormous spread beyond the bounds of the British Isles where it was originally a native tongue was the British Empire, and by the late nineteenth century its influence had won a truly global reach. It is the dominant language in the United States and the growing economic and cultural influence of that federal union as a global superpower since World War II has significantly accelerated adoption of English as a language across the planet.
A working knowledge of English has become a requirement in a number of fields, occupations and professions such as medicine and as a consequence over a billion people speak English to at least a basic level.
Linguists such as David Crystal recognise that one impact of this massive growth of English, in common with other global languages, has been to reduce native linguistic diversity in many parts of the world historically, most particularly in Australasia and North America, and its huge influence continues to play an important role in language attrition.
English is one of six official languages of the United Nations.
Source - Wikipeadia.com