October 16 is World Dictionary Day, marking the birthday of the great American lexicographer Noah Webster. Born in Hartford, Connecticut, in 1758, it was Webster’s two-volume American Dictionary of the English Language that truly earned him his place in linguistic history, and a reputation as the foremost lexicographer of American English. To mark the occasion, here are 10 facts about the dictionary without which Dictionary Day would not exist.

1. IT WASN’T WEBSTER’S FIRST BOOK ABOUT LANGUAGE ...

Following his studies at Yale in the late 1700s, Webster had initially hoped to become a lawyer, but a lack of funds held him back from pursuing his chosen career and he instead ended up teaching. It was then that he became horrified of the poor quality of school textbooks on offer, and took it upon himself to produce his own. The result, A Grammatical Institute of the English Language—nicknamed the “Blue-Backed Speller,” because of its characteristic cover—was published in 1783 and remained the standard language textbook in American schools for the next century.

2. ... OR EVEN HIS FIRST DICTIONARY.

Webster had published a less exhaustive dictionary, entitled A Compendious Dictionary of the English Language, in 1806. Although considered little more than preparation for the much larger project that lay ahead, Webster’s 1806 effort still defined an impressive 37,000 words, and is credited with being the first major dictionary in history to list I and J, and U and V, as separate letters. He began work on his American Dictionary the following year.

3. IT TOOK HIM 22 YEARS TO COMPLETE (FOR GOOD REASON).

Webster reportedly finished compiling his dictionary in 1825, and continued to edit and improve it for a further three years; he was 70 years old when his American Dictionary of the English Language was finally published in 1828. There was good reason for the delay, however: Webster had learned 26 languages—including the likes of Sanskrit, Ancient Greek and Old English—in the process.

4. IT WAS THE BIGGEST DICTIONARY EVER WRITTEN.

Webster’s 37,000-word Compendious Dictionary (1806) had listed around 5000 entries fewer than what was at the time the longest English dictionary available: Samuel Johnson’s 42,000-word Dictionary of the English Language (1755). But with the publication of the American Dictionary, Johnson’s record was obliterated: running to two volumes, Webster’s 1828 dictionary defined a staggering 70,000 words, around half of which had never been included in an English dictionary before.

5. NOT ALL OF HIS SPELLING REFORMS HIT THE MARK.

In compiling his dictionaries, Webster famously took the opportunity to make his case for spelling reform. As he wrote in the introduction to his American Dictionary, “It has been my aim in this work … to ascertain the true principles of the language, in its orthography and structure; to purify it from some palpable errors, and reduce the number of its anomalies.”

A great many of Webster’s suggestions—like taking the U out of words like colour and honour, and clipping words like dialogue and catalogue—took hold, and still continue to divide British and American English to this day. Others, however, were less successful. Among his less popular suggestions, Webster advocated removing the B from thumb, the E from give, and the S from island, and he proposed that daughter should be spelled “dawter,” porpoise should be spelled “porpess,” and tongue should be spelled “tung.”

6. SOME OF THE WORDS WERE MAKING THEIR DEBUTS IN PRINT.

Besides recommending updating English spelling, Webster made a point of including a number of quintessentially American words in his dictionaries, many of which had never been published in dictionaries before. Among them were the likes of skunk, hickory, applesauce, opossum, chowder and succotash.

7. WORDS BEGINNING WITH X WERE SUDDENLY A THING.

Samuel Johnson’s 1755 Dictionary had contained no words at all beginning with X. (“X is a letter,” he wrote at the bottom of page 2308, “which, though found in Saxon words, begins no word in the English language.”) Webster’s 1806 Compendious Dictionary increased that figure by one with xebec, the name of a type of Mediterranean sailing vessel. But in his American Dictionary, Webster included a total of 13 entries under X, namely xanthid and xanthide (a chemical compound), xanthogene (the base of a new acid), xebec, xerocollyrium (an eye-salve), xeromyrum (a dry ointment), xerophagy (the eating of dry food), xerophthalmy (the medical name for dry eyes), xiphias (a swordfish), xiphoid (a piece of cartilage at the bottom of the breast bone), xylgography (wood engraving), and xyster (a bone-scraper), as well as the letter X itself (“the twenty-fourth letter of the English alphabet … [having] the sound of ks”).

8. WEBSTER PREDICTED THE UNITED STATES’ POPULATION BOOM.

In 1828, the population of the United States was roughly 13 million; by 1928, that figure had increased nine-fold to more than 120 million, and today the US is home to around 320,000,000 people. Despite writing at a turbulent time in the country’s history, Webster somehow predicted the future expansion of America’s population almost perfectly. In the introduction to his American Dictionary, he wrote:

It has been my aim in this work, now offered to my fellow citizens, to ascertain the true principles of the language … and in this manner, to furnish a standard of our vernacular tongue, which we shall not be ashamed to bequeath to three hundred millions of people, who are destined to occupy, and I hope, to adorn the vast territory within our jurisdiction.

It was an oddly accurate prediction, and one that he reiterated under the word tongue (or rather, /tung), which he defined as “the whole sum of words used by a particular nation. The English tongue, within two hundred years, will probably be spoken by two or three hundred millions of people in North America.”

9. ITS PUBLICATION INSPIRED A CHANGE IN THE COPYRIGHT LAWS.

The publication of Webster’s dictionary—as well as his own newfound celebrity—led to a major change in United States law that provided indelible security for all writers and authors. In 1831, Webster was invited to the White House to dine with President Andrew Jackson, and subsequently to give a lecture to the House of Representatives. He took the opportunity to lobby the House to change United States copyright law, which at the time protected writers’ work only for a total of 14 years. The result was the Copyright Act of 1831, which extended writers’ protection to a total of 28 years with the option to apply for a further 14 years’ copyright after that.

10. IT WAS A SUCCESS … BUT NOT ENOUGH OF A SUCCESS.

The American Dictionary sold a quietly impressive 2500 copies—priced between $15 and $20 (roughly $350 and $480 today). But high printing and binding costs meant that even these sales weren’t enough to make the dictionary all that profitable, and consequently, at the age of 82, Webster was forced to mortgage his home in New Haven to finance an extended 2nd edition (including a further 5,000 new words) in 1841. Sadly, it failed to capitalize on the previous edition’s modest success.

Webster died two years later on May 28, 1843, after which booksellers George and Charles Merriam bought all unsold copies of Webster’s 2nd edition—crucially, along with the rights to publish revised editions in future. The Merriam-Webster Dictionary was born.