Why Is Ralph Wiggum SO Dumb in The Simpsons?

why is Ralph wigam so slow me fail English that's impossible Ralph's definitely not the sharpest kid in Springfield Elementary I'm a unitard but it goes more than that he's just a bit off overall like having an imaginary evil leprechaun has a friend who tells him to burn things leprechaun he told me to burn things so why well when raly was a baby his dad accidentally dropped him right on his head and therefore caused him to have longterm brain Dage my cat's breath smells like cat food