Used widely in commerce and international communication, English has three characteristics that make it stand out among the major languages in current use: Nouns and noun modifiers lack gender, the grammar is simple, and the language has an immense vocabulary that has drawn heavily on other major languages (The Story of English, Robert McCrum, William Cran, Robert MacNeil, Elisabeth Sifton Books, Viking Press, 1986, ISBN 0-670-80467-3). Moreover, it is spoken by more people than any other single language, and is the native tongue or offical language of countries scattered all over the world, with focal points in England, Australia, New Zealand, South Africa, The United States, and Canada (Edward Finegan, in The World's Major Languages, Bernard Comrie (Ed.), Oxford University Press, 1990, ISBN 0-19-520521-9, ISBN 0-19-506511-5. Estimates of the number of people who currently speak the language range from over one billion (McCrum, et al) to in excess of one-and-a-half billion (Wikipedia, 2011).
Developed from dialects brought to Britain by teutonic tribes invading from western Europe, English has evolved over the years from its Anglo-Saxon beginnings into several forms, Old English, Middle English, and Modern English. It is currently the lingua franca of the modern world.
The growth of English from its unlearned beginnings to its current position of importance in world affairs is the bright side of the picture. Literacy data gathered in the 1990's by the Adult Literacy Survey (ALS) reveal the dark side; that only 53 percent of those who speak the language can read and write; the lowest literacy level of any major language. That shouldn't be, and it needn't be. We can significantly improve the literacy levels of the English language by reducing the number of symbols used, limiting the speech values each symbol represents, and spelling words the way they sound; the aim and purpose of the Inglish spellings.
[A brief recap of the origins and growth of the English language is attached, if you're interested.]