She said "pizza" so many times that she lost track of what it means. I'm sure it helps that pizza is a somewhat foreign concept, but mostly it's just spamming her short-term memory with a sound so many times without thinking of the meaning that makes it harder to retrieve the meaning.
I'm sorry, but I don't really get this one. Is it just that there's no pizza in Gensokyo or is there a joke I'm missing?
I wrote the description for the joke that they were playing. The punchline was that Yuyuko suddenly mentioning an unexpected philosophical statement in the middle of a commonly known joke.
.... Hey, Youmu...I wonder...what is pizza?This must be the setup for a tongue twister...Pizza Pizza
Pizza PizzaKnowing that, I won't fall for it.Pizza Pizza
Pizza PizzaYoumu, can you say "pizza" ten times?
This is the intro of a famous "ten-times quiz (10回クイズ)" known in Japan.
Originally, the Q&A proceeds as in the following:
Q: "Say pizza 10 times."
A: "Pizza x 10."
Q: "(Pointing at the elbow) What's this part called?"
A: "Hiza ('knee' in Japanese)?"
Q: "Gotcha! It's hiji ('elbow' in Japanese)."
As you can see, it's a joke that tries to trick the answerer by making them speak a word that sounds and means similar before answering.
