I used to think "Dachshund" was pronounced "Dashhound". I called them Dash Hounds until I was 12 or so.
A childhood belief about cats and dogs

others believed things like this
- When I was little i thought lb for pounds was pronounced lubs, and i called them that for 2 years. Anon
- i used to believe that 'island' was pronounced 'is-land' instead. I know im not alone on that one! :)
— Da KornMeal - I used to think that New York was pronounced "Yew Nork"Anon
- when i was little i used to think bumble bee was actually pronounced bumbow bee— cathy
- I used to believe that L-M-N-O-P was 1 letter, pronounced elemenopeeAnon
- I used to believe that the name Giselle was pronounced "gazelle"— Derek