Just as many speakers of Asian languages have trouble distinguishing "L" and "R", lots of Arabs have difficulty in telling "P" and "B" apart. Since Arabic only has the "B" sound, "P" is unfamiliar to them. This can make for some hilarious mistakes if a native Arabic speaker hasn't quite mastered the nuances of English. Once I was sitting in class and on Mondays the teachers would always ask us what we did over the weekend. This particular teacher spoke and understood English very well, but still had trouble with "P" and "B". He'd say things like "banda bear" and the words "pet", "bet", "bit", and "pit" all sounded alike to him. He'd only be able to tell by context what you meant.
Well anyway, this one Monday he was going around the room and everyone was telling him what we did over the weekend. When he got to me I told him that I had watched the The Bourne Identity. When I said that he started to look a bit uncomfortable. He told me that I should keep things like that to myself. I asked him why and he said, "Porn isn't an appropriate topic for class." After the rest of the students and I explained to him why we were laughing so hard he realized his mistake.