History of English Part Four: Modern English
The period known as Modern English is generally considered to have begun during the 15th century. The factors defining what constitutes Modern English are the Great Vowel Shift and an increased standardisation of English, partly as a result of the arrival of printing technology.
The Great Vowel Shift was a major change in pronunciation which took place in a relatively short space of time in the south of England. It is not known for certain what caused the change, although some people believe it may have been related to the Black Death when there was huge social change through necessity.
Shortly after this, the invention of printing led to a standardisation of spelling and dialect, with the language of the educated south-east coming to be considered the standard, particularly after dictionaries formalised this notion. Books also became cheaper to produce and increasing numbers of people learned to read.
It is also possible to make a distinction between Early Modern English and Late Modern English. The difference revolves around vocabulary, with Late Modern English featuring a greater number of words. This was partly due to the Industrial Revolution and the need for new words related to technology and partly to do with the spread of the British Empire, which allowed words to be adopted from a great many other languages.