Towards the end of Middle English, a sudden and distinct change in pronunciation (the Great Vowel Shift) started, with vowels being pronounced shorter and shorter. From the 16th century the British had contact with many peoples from around the world.
This, and the Renaissance of Classical learning, meant that many new words and phrases entered the language. The invention of printing also meant that there was now a common language in print. Books became cheaper and more people learned to read. Printing also brought standardization to English. Spelling and grammar became fixed, and the dialect of London, where most publishing houses were, became the standard. In 1604 the first English dictionary was published.