The Unpastured Sea
Novelette 9,902 words Recommended by 2 award/anthology sources
"This is a story that Iya, the eldest and given to such fancies, told the younger children when all of them, even those from Kehinde (whose people live pressed against the ceiling, although to them it seems the floor), could gather and be made to listen. Tokunbo, adolescent and sullen, resented being so compelled..."
Quasar links out; the story lives on Asimov's, where the author gets the click.