Many years into the future, a human scientist came up with a wonderful device. It would boost human intelligence several times over and would finally allow humanity to enter the space age.
It could only be used once, but the booster would forever change human psychology. Greed, fear, and hatred would no longer rule the human mind. With their disappearance, religion, war, poverty, and discrimination would follow. Humanity as a whole would become, as they say, "lighter and softer".
But some people didn't want the device to be activated. They wanted their faiths to dominate all others. Their money to last to the next Pangea. Only their genomes to perpetuate. So they sent a group of mindless monsters to storm the scientist's lab. She valiantly tried to fight them off, but failed, and the device was destroyed...
Or so the monsters thought. In actuality, one of the device's prototypes was destroyed. And doing so let out a psychic shock that broke the minds of all humans, condemning them to an early extinction.
Centuries passed, and the world moved on. But one day, a firefly, mistaking its lights for the lure of a female, accidentally activated the finalized device. Some of each animal species in the world became sapient and anthropomorphic as a result of this accident. The firefly responsible took on the name "Edison" and helped to spread the lessons he'd learned studying the extinct primates to everyone else.
A new golden age was upon the world.
One of the many new and interesting inventions that the animals made were talking letters, because non-sentient letters just weren't good enough for advertising anymore. The letters were robots, essentially, AIs made of wires and computer chips built into a shaped silicone matrix and capable of changing their color and case as need be, though they were built uppercase by default since lowercase letters rarely appeared in advertising. The letters were meant to be friendly, sweet, and kind, with each one having a specific hat.
But of course, not all letters fit their stencils.
Tad, the youngest child of the marsh frog who helped bring the talking letters to life, noticed a hallway in the Word Factory he'd never seen before. Inside were many shelves, filled with black boxes with single letters painted on them. There were two guards, a lemming and a katydid, stationed outside it. "Dad?" he asked.
"What is it, Tad?" Mr. Charles Frog asked his son.
"What's that place?"
Mr. Frog looked over to what Tad had found and paled. "Oh. That's the...adult language section of the Word Factory. People younger than thirteen aren't allowed inside, hence the guards."
"Why not?"
"See those black boxes in there?" Tad nodded. "Those are words, just like 'mat' and 'fat' that you made earlier this year. But these words have different meanings." Mr. Frog noticed a mountain bluebird leaving the hallway with some black boxes on a cart. "Oh! Mr. Fluffkins! Can my son see those words before you ship them off?"
"Certainly," Mr. Fluffkins said, after showing his ID to the guards. He wheeled the cart over. "See this box?" he asked Tad, pointing to a box, four letters long and denoted with an "F" on each side.
"Yeah?"
"There's a word inside. You know how sometimes on TV someone says something but all you hear is a bleep?"
"I don't think I'm allowed to watch those shows..."
"You aren't, and these words are why. Kid, what do you say when you mess something up?"
"'Uh-oh'?"
"And what do you say when you're mad?"
"'Ergh'?"
"Bingo. Well, this word right here can be used those same ways. But we don't let just anyone say them." He suddenly growled at Tad. "Scared?"
"Y-yes, Mr. Fluffkins."
"Well, if I'd said this word, you'd be ten times as scared! Now take this one," he said, pointing to another box, also four letters long, denoted with an "S". "This word is another way to say 'poop'. But if I said this word you'd be ten times as grossed out! And this one?" he asked, pointing to a three-letter-long box denoted with an "A". "This word is used for people who are stupid or mean. So is this one," he added, pointing to a five-letter-long box marked with a "B". "If I called someone these words, they'd be ten times as mad as they'd be if I just called them stupid or mean."
"Oh, I see now," Tad realized. "To use these words you need to have a lot of experience with how to use words at all."
"Exactly," Mr. Frog said, nodding in approval. "And learning how to use words properly takes a very long time. So that's why we don't let people under a certain age use certain words. Like these four right here, and they're not even the worst ones, to be honest with you. Even then, they should only be used every once in a while since they have a big impact on how people feel."
"Do...do letters know these words?"
"We build the letters to know all words and what they mean," Mr. Fluffkins chuckled. "And they all know how to use them. Most of our stock just doesn't get used this way, but every now and then someone puts in an order for quality cusses. Listen, I gotta go drop these off. See you guys later." And he left, wheeling the cart away.
"So...what does the word beginning with 'F' mean?" Tad asked.
Mr. Frog gulped. "Uh...do you know where babies come from?"
"No?"
"Well, it's...not by a stork dropping them down a chimney...it's by doing what that word means. There are many ways to say it, that's just one of the...harsher ones."
"People sure use words in weird ways," Tad decided.
"That they do, my boy. That they do."
Light. Bright light. The AI blinked into existence. He looked himself over; he was a royal blue block with two triangular notches cut out in a way that made him symmetrical on the line x = y. He summoned a pair of tiny white hands from the nanobot deposits in his sides and scratched himself before retracting them.
The ground under him moved. It was then he realized that he was on a conveyor belt. He looked around, and saw several other blocks like him.
"What...are we?" he asked himself. He got his answer when he saw a glyph resembling his shape on the top of the doorway going out. "Some kind of...symbol? But for what?" He and his fellows continued on.
"Oh, very nice!" The AI saw a bizarre creature, bipedal with brown fur and a shock of scarlet hair behind each ear. A thin tail poked out from below the creature's white coat. "These are some of the best Z's I've seen yet!"
"Well, we did restock the pigment recently," another creature, this one gray-furred with black fur around their eyes, remarked.
"Send the Z's to their training room!" The belt shifted, and the AI blocks changed direction eventually reaching a new device that scanned them and assigned them numbers.
"Z-19995," it said to the block before him, which beeped away, then the next one moved up. "Z-19996. Z-19997. Z-19998. Z-19999." It reached him. "Z-20000. Congratulations."
"Uh...thanks?"
He passed through and saw a...horrifying...thing on the belt nearby. It was green and lumpy, with many loose wires and broken steel structural rods sticking out of its flesh. Worst of all, it made a dreadful squawking noise out of its two orange mouths. Thankfully, a scaly gray creature with red spots and flat fingers took notice of the thing and pressed a button that dumped it into...somewhere far down below.
Z-20000 shuddered. "Whatever that thing was, I do not want to find out." He reached the end of the belt and was unceremoniously dumped off it. His fellow Z's simply hopped on their bottoms. But Z-20000 decided to summon a small pair of feet and walked instead. "This ought to be much faster than just hopping," he said.
"Yeah, but it's weird!" Z-19998 shouted at him.
"That's your opinion," Z-20000 retorted. He was right, of course, and his feet took him far away from his bothersome brood to a hallway.
Z-20000 looked to his left, seeing a door marked with two glyphs, both cherry red. One of them was taller than the other and triangular, but the base wasn't at the bottom of its legs but instead further up. The other was a small circle with a line attached to its right side. He watched several cherry red blocks resembling the bigger glyph, their mouths taking the place of the hole in the middle, approach the room.
"Hello!" he said cheerfully. The glyphs screamed and quickly ran into the room behind the door. "Geeze, tough crowd."
"A's are naturally cowardly." Out of the room came a much larger red glyph, a female. "It's how we learn our sound. 'Ah'."
"Ah. Uh...do you know where I go?"
"You're a Z. Your room is at the very end of the hallway."
"Oh. Thank you very much." He continued on.
"Funny little letter," the Teaching A, naturally bigger than the standard-production A's as she was meant to train, remarked. "He acts like a grown-up, but the lack of scuff marks on his bottom means he's only been alive for today. Most peculiar." Thinking nothing more of it, she went back inside her room, shutting the door behind her.
Z-20000 walked down the hallway, seeing several more colorful glyphs inscribed onto various doors. Two dozen, to be exact. Each with their own color and...quirkiness.
The second room had yellow-green letters and was loud and terrifying.
The third had azure letters and was exceptionally frigid.
The fourth had purple letters and felt...out of date. By millennia. Still, the music inside calmed Z-20000 down when he passed by.
The fifth had fern green letters and creaked softly.
The sixth had yellow-orange letters and felt drafty.
The seventh had yellow letters and smelled of sweat.
The eighth had orange letters and felt uncomfortably warm.
The ninth had light yellow-green letters and...was that slime coming through the crack beneath the door?
The tenth had magenta letters and also played outdated music. Annoying music. Z-20000 felt like kicking whoever chose that music. Hard. Preferably somewhere soft and delicate.
The eleventh, speaking of kicking, had manila letters and played much less annoying music inside.
The twelfth had grass green letters and smelled of sugar.
The thirteenth had baby blue letters and smelled even more of sugar.
The fourteenth had red letters and the door was boarded up.
The fifteenth had light pink letters and the air coming from beneath the door was humid.
The sixteenth had light yellow letters and smelled of popcorn. Whatever that was.
The seventeenth had green letters of the same color as the...horrifying monstrosity, but the squawks inside were much more eloquent, suggesting that these blocks had turned out right.
The eighteenth had red-orange letters and smelled of burnt rubber.
The nineteenth had iris purple letters and faint hissing sounds came from inside.
The twentieth had mint green letters and clicking noises came from inside.
The twenty-first had amber yellow letters and was also drafty.
The twenty-second had light purple letters and shook uncontrollably.
The twenty-third had vermillion letters and played the cringiest music of all.
The twenty-fourth had blue-green letters and now and then the light coming from inside turned black.
The twenty-fifth had dull orange letters and screaming came from inside.
And finally, Z-20000 found his room, whose door had two-different sized glyphs both shaped like himself, a room which was dark, calm, and tranquil. He entered it, then shut the door behind him.