I have a friend who, up until about 6 months ago, thought the color turquoise was actually "turk boys". He is 23 years old, by the way.
A childhood belief about speaking

others believed things like this
- I never knew why boys had to lift up the toilet seat...until my friend told me that boys had bad aim.Anon
- my friend, up untill she was in her early 20s thought that if you drank gatorade you would sweat in colorAnon
- My sister used to think that because I was 15 months older than her, I would die 15 months before her!— Nicola Braden
- I used to believe the Beastie Boys were a boy band. Well, the name sounds similar to Backstreet Boys!Anon
- When I was 5, I argued with a friend because I thought I never have been 3 years oldAnon
- When I was around seven years-old, my friend and I put a rock in a microwave and thought it would melt.— Lars