I am third-generation Japanese (my grandparents were born in Japan and moved to the United States). My brother and sister used to believe that when they were young, they would only know English, when they were our parents' age, they would know both English and Japanese, and when they were our grandparents' age, they would forget the English and only speak Japanese.
A childhood belief about foreign languages

others believed things like this
- My older brother made me believe that wristwatches were powered by tiny Japanese men inside them.— Outsider
- i used to believe that i am american.
i am japanese . — mayumi - I used to think that even people who spoke something other than English, thought in English— Peaches
- I used to believe that my dog could speak English, but he just didn't feel like it.— Mariah
- I remember thinking that non-English speakers were much smarter because they could speak "so much faster." Anon
- I used to think everyone in the world knew and thought in English, but choose to speak different languages. Anon