Said by many, my guess is they cant pronounce the word open correctly it. People who say ompen also say things like Ompinion,Omprah,Ompium,Hompefully and they might say the wird company funny too.
Robert Plant Singer of Led Zepplin says ompen in Kashmir and Over the Hills.
R. Kelly says ompen in I belive i can fly.
made famous by wendell; ompen-said instead of saying open; random word used in mumbling by wendell. speeking this word may lead to other mispronunced words such as work'nem plot'nem drop'nem
"promp that door ompen!"