For as long as microfiction has been a doctrine, there have been those who would test its boundries. Not content with the creation of stories only a few hundred words long, countless authors have made attempts at nanofiction, with the most famous being Hemingway’s six-word short story, “Baby shoes for sale; never worn.”
Delving even deeper into the fractal rabbit-hole, there have even been studies in picofiction, seeing how much meaning or emotion can be conveyed with a single word. Here is where the often amorphous line between fiction and poetry breaks down, but for the sake of argument, we will assume that poetry can be a form of fiction, and leave it at that. An example of picofiction would then be Aram Saroyan’s poem, “lighght”, for which he won the National Endowment for the Arts, despite criticism that it was “not a real poem” and “not even spelled correctly.”
Anything beyond femtofiction is a purely theoretical structure, as such a thing would be only a few hundredths of a letter long. There have been claims that music is in fact a form of femtofiction, as a single note is still able to convey emotion, but such claims are still hotly contested.
So far, there have been no claims as to the creation of attofiction. The main obstacle to this seems to be the cumbersome nature of the English language, and the physical restrictions of the human vocal cords. To create attofiction, one would need to create a hypothetical language of unimaginable brevity, and then gain the ability to speak it by making sounds fractions of a millisecond long. However, this skill alone would not attofiction make. You would need a second party to also learn this language, so as to have someone to understand your words. And finally, to your sole listener in the world, you would need to speak something beautiful.