When I was little I used to think a suitcase was called a "soupcase". I called it this for many years before I figured it out and no one noticed.
A childhood belief about speaking

others believed things like this
- I believed that the breed of dog called Boxer was called that because they could stand up and box.Anon
- My mom used to think "preschool" was called "pretty school" until a few years later.— Molly
- I used to believe that people from Holland were called "Hollish", like people from Poland are called "Polish"— Sally
- I used to think that adult kangaroos were called Kangas and that child kangaroos were called Roos. Anon
- When I was little i thought lb for pounds was pronounced lubs, and i called them that for 2 years. Anon
- I used to think that because there was a state called Washington, there was also a state called Dryington.— Jasonchic