When we think about how the world will change in the coming centuries, we’ve come to expect flying cars and other technological advances. One thing we rarely think about is how language will change. But if you travel 500 years into the future, you might not recognize your own native tongue. As National Geographic’s new series Origins (Mondays at 9/8 CST) explains, human communication is always evolving, even if the shifts happen too slowly for us to recognize.

Here are seven signs that language has shifted over time—and that it’ll continue to morph.

1. SHAKESPEARE IS HARD FOR MODERN ENGLISH SPEAKERS TO DECODE.

William Shakespeare didn’t live all that long ago, as far as the relative scope of history goes. But his 16th and 17th century plays now come with enough vocabulary-related footnotes to fill an entire separate book. It’s more than just the addition of archaic pronouns like “thee” and “thou.” The word “boot,” for instance, is more than just a footwear reference in Shakespeare’s writings—it might mean an advantage or an additional element, too. He also invented words we still use today. We have him to thank for everyday words like “arch-villain,” “bedazzled,” and “new-fangled.” Flipping through Shakespeare’s verses is a master course in how quickly a language can evolve into a whole different beast. Just try to imagine ol’ Billy Shakespeare reading the transcript of an AIM chat.

2. PRONUNCIATION IS STILL CHANGING.

Between the 12th and 18th centuries, the English language experienced something called the Great Vowel Shift, changing the pronunciation of all the long vowels. In Middle English, the word “sight” would sound like “seet,” while the word “boot” would sound like “boat.” However, pronunciation changes aren’t limited to centuries ago. In modern American English, the sounds “o” and “au” are merging, so that words like “stock” and “stalk” now sound like homophones in many regions of the U.S. While this sound merger has existed for generations in New England, other regions used to maintain a difference in pronunciation between the two vowel sounds. Now, the sonic merger is spreading, and nearly everyone in the western United States rhymes “lot” and “bought.”

3. DICTIONARIES ADD NEW WORDS ALL THE TIME.

Dictionaries, the major arbiters of official language usage, aren’t stagnant entities. Editors regularly add new words to reflect popular usage, often expanding reference books by thousands of words. In 2015, one prestigious dictionary added Internet-friendly terms like “clickbait” and “photobomb” as well as terms that reflect new scientific and technological advances, such as “neurofeedback” and “colossal squid.” In 2016, the same dictionary added “Mx.,” the gender neutral title, and “TMI.” The evolution of slang reflects the fact that people are inventing new terms to describe the modern world all the time, even if it takes a while for “official” language sources to catch up.

4. BLENDED WORDS STICK.

As the world changes, people combine words to create terms for things that may not have existed before. The word “motel,” coined in the 1920s, is technically a mixture of “motor” and “hotel,” though we no longer think of drivers as “motorists.” The word “smog,” a mixture of smoke and fog, didn’t come around until the early 1900s, serving as a response to the unprecedented air pollution the industrial revolution brought to London. Not all word blends describe completely new ideas, though. The word “humongous” first came into the world around 1967, and is probably a combination of “huge,” and “monstrous,” according to one dictionary.

5. VERBS HAVE BECOME NOUNS, AND NOUNS HAVE BECOME VERBS.

Some common verbs weren’t so common until fairly recently. Being a parent is now a verb: parenting. We don’t just read a text, we text each other. The first known use of “to escalate” didn’t occur until 1922: it was created through what’s called a back-formation from the word “escalator.” The word “destruct” came into English in the 1950s in the same manner, as a back-formation from “destruction.”

6. DEFINITIONS CHANGE.

Think of the word “millennial.” Just a few decades ago, it simply referred to a period of a thousand years, or a millennium. Now, it’s a ubiquitous term for the generation of people born in the 1980s and 1990s. In Chaucer’s time, “girl” could refer to a child of either sex, while even through the 1700s, “meat” could mean any kind of solid food. In the 1600s, the word “cheater” referred to an official who looked after the king’s lands. Thanks to the dishonest tendencies of those officers, the word now refers to a swindler.

7. OLDER GENERATIONS HAVE ALWAYS COMPLAINED ABOUT NEW-FANGLED WAYS OF SPEAKING.

Lamenting the loss of “proper” speech isn’t limited to modern adults who think “LOL” and “ROFL” are ruining the English language. In 1712, Jonathan Swift complained that poets abbreviating words to fit in verse was a “barbarous custom.” Young men, he wrote, are too impressed with their own slang. He complained that they “borrow the newest Sett of Phrases, and if they take a Pen into their Hands, all the odd Words they have picked up in a Coffee-House, or a Gaming Ordinary, are produced as Flowers of Style.” Researchers are still arguing about whether that particular essay was satirical or a true lament on the declining standards of the English language, but either way, Swift’s complaints don’t sound that different from those who now complain about the Internet-y terms of the 21st century.

From communication to medicine to war and more, National Geographic’s new series Origins rewinds all the way back to the beginning and traces the innovations that made us modern. New episodes, Mondays at 9/8 CST.

Learn more at NatGeoTV.com/Origins