When I was young my uncle told me that "the Japanese read backwards" (Meaning actually that they read from right to left.) I took this to mean that to speak Japanese I just had to learn to speak backwards. Like, sdrawkcab is Japanese for backwards... I practiced for a while, then met a Japanese kid who said that's not how it works. I don't trust my uncle very much anymore. ;-)
A childhood belief about foreign languages

others believed things like this
- i used to believe that i am american.
i am japanese . — mayumi - My older brother made me believe that wristwatches were powered by tiny Japanese men inside them.— Outsider
- I used to believe that if I spelled Norwegian words backwards, it would be English. I don't anymore...— Gudrun
- My brother used to believe that when we went to school dogs went to dog school to learn to speak and read— Matt
- i used to think that french was english backwards!— ---pepsi---
- I used to think that Russian was just English backwards— Millie