When I was a little kid there was a short on Sesame Street about the letter G. At the end the guy said something like "and G also stands for (starts cracking up) Giggle! (bursts out laughing)". For the longest time, I misheard "giggle" as "eagle" and didn't get why he said that, as even as a kid I knew that was wrong, or what was supposedly so funny.
A childhood belief about spelling

others believed things like this
- I used to believe that “Emo” was related to Elmo from Sesame Street.Anon
- I seriously used to believe that Bert from Sesame Street lived in my closet and that he was going to kill me.— Liz
- I used to believe that Eagle Brand Condensed Milk was actually an eagle's milk!Anon
- I thought that Count Dracula was the count from Sesame StreetAnon
- For the longest time I didn't know that Spinal Tap wasn't a real group. No wonder I couldn't find their music.— Louis
- i really thought that "key" was a secret letter to the alphabet that only i knew.— amber