My mother always has a habit of speaking too quickly, and running words together. Until I reached high school I was convinced that the phrase 'I might add' was actually, 'on my dad', and was puzzled why anyone would say such a thing.
A childhood belief about speaking

others believed things like this
- When I was young, I honestly believed that I would die before I reached high school. Anon
- I thought the phrase "At one's disposal" meant you should dispose of the person or thing.— Geirskogul
- I used to believe that people who were speaking foreighn languages were just speaking gibberish.— Zoe
- a friend was convinced that his school was an asylum, and couldn't be convinced otherwiseAnon
- I used to believe that you got married right after you finished high school or college. Anon
- I thought that wars had to last four years... just like high school and college.— A. Falk