Modern English is the form of the English language spoken since the great vowel shift, completed in roughly 1550.Despite some differences in vocabulary, material from the early 17th century, such as the works of William Shakespeare and the King James Bible, is considered to be in Modern English, or more specifically, they are referred to as Early Modern English, and most people who are fluent in the English of the early 21st century can read these books with little difficulty.Modern English has a large number of dialects, spoken in diverse countries throughout the world. Most of these, however, are mutually intelligible. This includes American English, Australian English, British English, Canadian English, Caribbean English, Hiberno-English, Indo-Pakistani English, New Zealand English, Singaporean English and South African English. These dialects may be met in different contexts, for example some American actors in Hollywood historical or mythic epics often employ British-derivative
Source:
http://en.wikipedia.org/wiki/Modern English