Johann Gutenberg invented the printing press in Germany around 1450, and then William Caxton introduced it to England in 1476. Five major dialects of English existed at that time and as early as the 1430s the Chancery of Westminster had made efforts to standardize spellings for written documents of English. With the printing press the standardization success blossomed. Choices of publishers quickly influenced the evolution of English.
About a century later, the first English dictionary was written: “A Table Alphabeticall” by Robert Cawdrey in 1604. The Italians had theirs 8 years earlier and the French 35 years earlier. While the Arabs had theirs 800 years earlier and the Indians had their first Sanskrit dictionary 1,000 years earlier. Mass distributed dictionaries were published over the next 150 years and the standardization of English progressed hugely.
I think it is because with our long history of fairly standardized English, the average person today is often blind to the real nature of language. They think that words have real definitions, real meanings. But with only a little study, it is clear that language, by nature, is constantly changing. Running into such illusions I stability I constantly challenge language prescriptionists by saying:
“Language is a temporary cooperative contract between people.”
Source & Inspiration: The History of English — an excellent website