Before the mid-15th century, language in Europe was a local and fluid affair. Words were spoken, handwritten, and heard. A scribe in London, a merchant in York, and a poet in Kent might all consider themselves speakers of "English," but the way they wrote that language could differ dramatically. Spelling was a personal choice, guided by phonetics and regional dialect more than any fixed rules. Grammar was flexible, and the letters used in practice could vary. All of this came to an end with the invention of Johannes Gutenberg's printing press at some point between 1450. While its impact in helping to spread ideas is the stuff of legend, its more profound and enduring influence was subtler and more straightforward: the printing press did not merely disseminate language; it froze, codified, and standardized it, giving the world the modern concept of a single national language out of the morass of countless regional dialects.
The mechanism of this change was economic and technological. Before print, every book was a unique manuscript, copied by hand. A scribe would naturally write in his native dialect, using the spellings and grammar forms in which he learned to write when a boy. A book printed in one town might differ in appearance and sound from the same book printed in another. There was no "right" version; there were only differences. The printing press brought in the idea of mass production. Suddenly, hundreds of copies of the same text could be created from a single set of locked-in, unchangeable type. Such a simple fact made variation uneconomical. After a typesetter had carefully set thousands of metal letters onto a page, he was not going to change the spelling of a word for a variety of customers. The one he chose was, in effect, the one that was frozen and printed.
This gave a powerful incentive for standardization. Printers were businesspeople operating in a competitive marketplace. In order to market books to as large a public as they could manage, they had to use a variety of languages understood by the masses. By default, they tended toward the prestige dialect of the wealthy and city dwellers—the language of royal court, government, and commercial capital. In England, that was the East Midlands dialect, used inside and around London. This dialect, which Chaucer spoke a century earlier and now the court as well as the emergent merchant class use, formed the foundation for "Chancery English," the language of official writing. Printers adopted and formalized this form because it possessed the widest possible audience. As books printed from London presses spread throughout the country, they carried this London-standardized variety of English with them, slowly pushing regional dialects' written forms, like Northumbrian or West Country, onto the periphery.
One of the more direct results was spelling standardization. In manuscript culture, the word "night" could be spelled "niht," "nyght," "nite," or "night" and be perfectly acceptable, even within the same document, and all would be correct. A printer was not so flexible. For consistency across a print run and to facilitate the typesetting, they would select one spelling. Eventually, through repetition and widespread distribution, this chosen spelling was the "correct" spelling. The apparently arbitrary, phonetic spellings of the manuscript age began to look antiquated, rural, and unlettered. The printed page brought with it a visual uniformity for words so that there was a fixed association between a succession of letters and the word they represented. This placed reading and writing in a more teachable and learnable category, as the written word was no longer a moving target.
The printing press was also a good filter for vocabulary and grammar. With limited fonts and a limited number of type pieces, printers had a practical incentive to favor some words over others. A word employed in the London dialect was more likely to be cast in type than a rare regional idiomatic expression. As such, London-oriented books became the model to emulate, and the vocabulary they contained became authoritative. Words that were local and were not adopted by the printers began to fall out of written use, and eventually, out of formal speech. Grammar, too, emerged. The adaptive and unstructured syntax of manuscript works gradually gave way to the more invariable grammatical structures of printed books. The written text itself then became the de facto grammar handbook, imposing conventions of sentence structure, verb conjugation, and punctuation that were subsequently imitated by everyone who wished to be seen as literate.
It had a highly social consequence. It created a new, tangible distinction between the "proper" language of the printed page and the "improper" dialects of regional, spoken languages. A person's speech, once only their local dialect, might now be measured against a normative, national standard and found wanting. This elevated the status of the standardized version and began to stigmatize local varieties as unschooled. The ability to read and write this standard language then became a social marker and a prerequisite for entry into power, school, and the growing universe of print culture. It was the beginning of the idea that there is a "right" and a "wrong" way of using one's own home language.
Further, the permanence of print helped to sanction a specific moment in a language's evolution. William Caxton, England's first printer, and the printers of Paris established the standard for English and French, respectively. As the spoken ones went on their way, altering and developing, the written one, stabilized by the weight of millions of identical books, changed at a far more sedate pace. This created a widening divergence between the word uttered and the word set down, a divergence to this day. The written word gave language a durability and a history it previously did not have. Individuals were now able to read a book printed half a century earlier and find a firm language to read, opening the door to the study of literature and to the idea of linguistic heritage.
The impact of this revolution in language is ubiquitous. The fact that you can read these words and understand each one regardless of where you are located in the English-speaking nations of the world is a direct result of the printing press. The dictionary on your shelf, with its ultimate spellings and definitions, is a legacy of the print age's codifying imperative. The way we are taught grammar in school, complete with its fixed rules, was born from the norms established in the workshops of 15th and 16th-century printers.
In effect, the printing press transformed language from a local, oral river, with its ever-changing course with each turn, to a national, written canal, constructed for conformity and mass navigation. It replaced the flowing, personal script of the scribe with the stiff, public uniformity of the printed page. And in doing so, it created the national instruments of modern identity—a unified, standardized language that millions could share, and the sense of common culture that was above local attachments. The press didn't give us just books; it gave us the notion of "proper" English, French, or German itself, and the linguistic basis on which our modern nations and global communication are built.
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