The final major factor in the development of Modern English was the advent of the printing press, one of the world’s great technological innovations, introduced into England by William Caxton in 1476 (Johann Gutenberg had originally invented the printing press in Germany around 1450). The first book printed in the English language was Caxton's own translation, “The Recuyell of the Historyes of Troye”, actually printed in Bruges in 1473 or early 1474. Up to 20,000 books were printed in the following 150 years, ranging from mythic tales and popular stories to poems, phrasebooks, devotional pieces and grammars, and Caxton himself became quite rich from his printing business (among his best sellers were Chaucer’s “Canterbury Tales” and Thomas Malory’s “Tales of King Arthur”). As mass-produced books became cheaper and more commonly available, literacy mushroomed, and soon works in English became even more popular than books in Latin.

At the time of the introduction of printing, there were five major dialect divisions within England - Northern, West Midlands, East Midlands (a region which extended down to include London), Southern and Kentish - and even within these demarcations, there was a huge variety of different spellings. For example, the word church could be spelled in 30 different ways, people in 22, receive in 45, she in 60 and though in an almost unbelievable 500 variations. The “-ing” participle (e.g. running) was said as “-and” in the north, “-end” in the East Midlands, and “-ind” in the West Midlands (e.g. runnand, runnend, runnind). The "-eth" and "-th" verb endings used in the south of the country (e.g. goeth) appear as "-es" and "-s" in the Northern and most of the north Midland area (e.g. goes), a version which was ultimately to become the standard.

The Chancery of Westminster made some efforts from the 1430s onwards to set standard spellings for official documents, specifying I instead of ich and various other common variants of the first person pronoun, land instead of lond, and modern spellings of such, right, not, but, these, any, many, can, cannot, but, shall, should, could, ought, thorough, etc, all of which previously appeared in many variants. Chancery Standard contributed significantly to the development of a Standard English, and the political, commercial and cultural dominance of the "East Midlands triangle" (London-Oxford-Cambridge) was well established long before the 15th Century, but it was the printing press that was really responsible for carrying through the standardization process. With the advent of mass printing, the dialect and spelling of the East Midlands (and, more specifically, that of the national capital, London, where most publishing houses were located) became the de facto standard and, over time, spelling and grammar gradually became more and more fixed.

Some of the decisions made by the early publishers had long-lasting repercussions for the language. One such example is the use of the northern English they, their and them in preference to the London equivalents hi, hir and hem (which were more easily confused with singular pronouns like he, her and him). Caxton himself complained about the difficulties of finding forms which would be understood throughout the country, a difficult task even for simple little words like eggs. But his own work was far from consistent (e.g. booke and boke, axed and axyd) and his use of double letters and the final "e" was haphazard at best (e.g. hadde, wel, whiche, fellow/felow/felowe/fallow/fallowe, etc). Many of his successors were just as inconsistent, particularly as many of them were Europeans and not native English speakers.

A good part of the reason for many of the vagaries and inconsistencies of English spelling has been attributed to the fact that words were fixed on the printed page before any orthographic consensus had emerged among teachers and writers. Printing also directly gave rise to another strange quirk: the word the had been written for centuries as юe, using the thorn character of Old English, but, as no runic characters were available on the European printing presses, the letter “y” was used instead (being closest to the handwritten thorn character of the period), resulting in the word ye, which should therefore technically still be pronounced as “the”. It is only since the archaic spelling was revived for store signs (e.g. Ye Olde Pubbe) that the "modern" pronunciation of ye has been used.

As the Early Modern period progressed, there was an increased use of double vowels (e.g. soon) or a silent final "e" (e.g. name) to mark long vowels, and doubled consonants to mark a preceding short vowel (e.g. sitting), although there was much less consensus about consonants at the end of words (e.g. bed, glad, well, glasse, etc). The letters "u" and "v", which had been more or less interchangeable in Middle English, gradually became established as a vowel and a consonant respectively, as did "i" and "j". Also during the 16th Century, the virgule (an oblique stroke /), which had been a very common mark of punctuation in Middle English, was largely replaced by the comma; the period or full-stop was restricted to the end of sentences; semi-colons began to be used in additon to colons (although the rules for their use were still unclear); quotation marks were used to mark direct speech; and capital letters were used at the start of sentences and for proper names and important nouns. The grammarian John Hart was particularly influential in these punctuation reforms.

Standardization was well under way by around 1650, but it was a slow and halting process and names in particular were often rendered in a variety of ways. For example, more than 80 different spellings of Shakespeare’s name have been recorded, and he himself spelled it differently in each of his six known signatures, including two different versions in his own will!