A reader in Australia writes to speculate on some other effects of this 463-year-old book -- and that's the title page of the 1549 edition at right:
Literary scholarship has long debated the reasons for the dramatic slowdown in the evolution of English that began to occur around 1600, and which is easily observed by noticing that the English of Chaucer (1400) and of Shakespeare (1600) are far more different from each other than Shakespeare's is from today's, even though twice as much time has passed.
When I did a PhD in theatre, mostly Shakespeare, at Stanford, we often flattered ourselves with the idea that the veneration of Shakespeare from the late 1600s onward helped to slow the pace of evolution in spoken English. But of course the KJ Bible and the Book of Common Prayer are probably at least as responsible, and like Shakespeare, their power lay entirely in that they were spoken texts, guiding a partly illiterate audience through repetition. If Shakespeare can still claim a role, it's probably the effect of his lower-class characters and scenes, which are one of the few places where a colloquial English was set down in a form so authoritative that later centuries would want to understand it, and perhaps unconsciously hold on to some of its rhythms and textures.
The other common explanation, Gutenberg's printing press, is responsible for a longer-cycle of slowing, but can't really explain why the evolution of the spoken language slowed so dramatically after the late 1500s. It took 200 years for books and literacy to become so common that the spoken langauge began ceding to written language as the authoritative form.
By the Victorian era, the official English was the written one, and the change of the language slowed down even more. Dickens is 150 years gone -- enough time for a medieval language to change beyond comprehension -- but he scarcely requires footnotes.
I wonder, though, if language change is about to accelerate again, as more and more of our attention is drawn online to immediate text. It feels like the conditions that stabilized English in the last two centuries -- a canon, widespread education in "classics," a preponderance of deliberative written text over instantaneous converstation -- may be slipping away.