Modern English is often dated from the Great Vowel Shift (a major change in the pronunciation of the English language), which took place mainly during the 15th century. By the time of William Shakespeare (mid-late 16th century), the language had become clearly recognizable as Modern English. In 1604 the first English dictionary was published. In 1755, Samual Johnson published the first significant English dictionary, his Dictionary of the English Language, which was influential in establishing a standard form of spelling.
The main difference between Early Modern English and Late Modern English is vocabulary. Late Modern English has many more words, arising from two principal factors: firstly, the Industrial Revolution and technology created a need for new words; secondly, the British Empire at its height covered one quarter of the Earth’s surface, and the English language adopted foreign words from many countries.
At the same time English was adopted in regions around the world, such as North America, India, Africa and Australia through colonization by the British Empire. Public education increased literacy, and more people had access to books (and therefore to a standard language) with the spread of public libraries in the 19th century. World War I and World War II threw together people from different backgrounds, and helped to lessen the differences between social accents, at least in the UK. This process was strengthened with the development of radio broadcasting in the early 20th century and continued with film and television.