I used to think the word "procrastinate" meant to put off going to the toilet. I couldn't work out why we needed a word to describe that - why didn't people just go to the toilet when the needed to go?
A childhood belief about speaking

others believed things like this
- my nephew used to believe that when people died, they just needed new batteries.— p-daddy
- In first grade, I thought that if I've never heard of a word before, then it wasn't a word.— Destiny
- my husband believed, until recently, that the word "several" meant seven of something. — sheryl
- I used to think the word fever was just another word for giraff— Marshall m
- I used to believe that "nuptial" was a naughty word. I thought it meant nipple. XD— Sara Hagen
- i used to think the word "friendship" meant a special kind of rocketship that you went on with your friends.— chips ahoy!