there's no "p" in the arabic language. a lot of arabs do have trouble pronouncing the sound and a "p" often turns into something like a "b."
my very first arabic professor once told this story about when he first came to the u.s. as a student. he lived in berkley and didn't always understand the lingo on the signs on the side of the road. one day he asked a police officer "can i bark here?" "you can bark whenever you want, it's a free country." the officer replied.
anyway, that's not nearly as embarrassing as this guy's story.
(via nina (aka spouse of dave))