Shakespeare’s rural backound has been a great influence on him and his plays. Unlike his contemporaries, Shakespeare didn’t go to university (Oxford or Cambridge), and as such didn’t have an opportunity to loose his accent (which is fairly average of what happens at universities). Not only was his lack of formal education fuel for ridicule from his fellow playwrights, his rural Warwickshire accent was too.
In reality, these two things were to work in his advantage, if not at the time but certainly since then.
Shakespeare was the only writer of his contemporaries to write plays which were set in rural locations in the UK. Henry IV Parts I and II were all set across various parts of the country, including his home county of Warwickshire, as was Henry V. The Merry Wives of Windsor, whilst set in Windsor, could essentially be about any small town life in England. He not only set his plays in rural England but was able to draw on his local knowledge to refer in the text real towns, building, public houses and the way of the land such as hills and valleys. He also wrote in local dialect, scenes and characters set in Gloucester were written using the local phrases and language and different from those set in Warwickshire or London.
Whilst these are reserved for a few select plays, mostly the histories, I speculate that this may well have been part of his popularity and success as writer at the time. London was a city of transition, people moving in and out of the city from across the globe but also from across the UK. As people travelled from across the UK to London, a disorientating experience in itself, they would have been greeted with an onslaught of different languages, dialects and accents, an even more disorienting experience. The opportunity to watch a play with your local dialect, or one you are familiar with, would’ve been very welcoming.