I used to think that weasel was short for wooden easel, and was confused as to why someone would be called a piece of art equipment as an insult.
A childhood belief about speaking

others believed things like this
- i used to believe that one piece of ear wax was actually called a wach. — rachael
- Since the girls name Jackie is short for Jacqueline, I thought the boys name Jack was short for JackalAnon
- I used to think that the UK was short for Ukraine.— Mia
- I used to think Obama's name was short for Baraccobama.— Trisha Gaurav
- I used to think monk was short for monkey.Anon
- I used to believe that accord was short for accordionAnon