As a small child I believed that the word was "nakeup", finally I found out that it was actually "makeup".
A childhood belief about speaking

others believed things like this
- few years ago, finally I found out that asparagus are not big sea fishes.. — nixass
- I used to believe that a vitamin was a small animal
only recently I have found out that it is not true... :)— Sylwia - As a small child I always confused someone being unconcious with someone being dead.— Rick
- my husband believed, until recently, that the word "several" meant seven of something. — sheryl
- I believed that the word optimistic was something to do with opticians and being happy with your eyesight.Anon
- Like most kids growing up, I believed there was an upside-down word on the other side of the mirror.— Taylor (14)