The early modern period was an era of great change for the English language. According to the OED’s record, the number of words ‘available’ to speakers of English more than doubled between 1500 and 1650. Many of the new words were borrowed into English from the Latin or Greek of the Renaissance (for example, hypotenuse), or from the far-off countries visited by travellers and traders (e.g. pangolin), and must have seemed hard to understand to many of the population.
At the same time, there were significant demographic shifts in Britain towards an urbanized culture based in the big cities, such as London: the population of London increased eightfold over these years. In retrospect, one can argue the growing availability of books and other printed matter as the period developed–alongside the emergence of the grammar school as a focus for education (especially for boys)–meant that the scene was set for the emergence of the English dictionary.