"You need a what? a school? What's a 'Sko-uh'? Do you need to go potty?"
She kept saying it, and I followed her to where she was leading while repeating her need for a "sko-uh". Then I got it, "Oh, you need a STOOL" She needed a stool to get up to the potty. I moved it back over from the sink, and she stood up on her stool and said "I need a bike."
"A what? A bike?"
"Yeah, I need a bike" and I realized she needed her potty seat that goes on top of the toilet.
She usually knows what that kind of stuff is called. I don't know where her vocabulary went today, but she's gonna love this story in a few years...