My nephew used to think that when people got old, they developed a foreign accent. This is because both sets of his grandparents were Jewish immigrants from eastern Europe, and they (and the rest of the family of their generation) all had accents. So he thought it was part of getting old. This was revealed to the family when he was about 4, and one of his mother's friends brought her Dutch boyfriend to the house for dinner. My nephew said in amazement, "He's young, and he has an accent already!"
A childhood belief about getting older

others believed things like this
- my nephew used to believe that when people died, they just needed new batteries.— p-daddy
- For along time I thought the Middle East and Eastern Europe were just different names for the same place!— Helllowerer
- When I was little I thought that Shakin' Stevens was Elvis' nephew— Ali
- My nephew (age 7) thought tampons were plugs for diarrhea. Anon
- My 7 year old nephew holds the opinion that the correct name for a pidgeon is a "city chicken".— Bastard
- My nephew refuses to put his tooth under his pillow in case the fairy burns him with her wand.— Nina