You know how adults sometimes spell out words that they don't want kids to understand? Well whenever grownups did this around me I could usually figure out what they were spelling, and so the point of doing this was pretty much defeated. So I just thought spelling words was a Thing adults did sometimes, and I would spell random words as I was speaking sometimes in an attempt to sound grown-up.
A childhood belief about spelling

others believed things like this
- I Used To Believe That Jail & Prison Are Both Timeouts For Adults/Grownups— Kelly Bulanek
- I used to believe that all four-letter words are bad words.Anon
- I used to think that I was smarter than adults. Now I know kids are smarter than adults in many ways— Marshall M
- I thought that kids' pee was yellow and adults' pee was clear.— Aretia
- I thought cartoons were for kids and "real-life programs" for adults.— Ichigo
- That adults came into the world as adults and were never childrenAnon