Mai Mowafy Aug 9, 2012:

You are welcome Amal :)

Arabic & More (asker) Aug 9, 2012:

Thank you, Rabbas. It is interesting to read about the origin of the expression. Again, though, people in the U.S. definitely say, "When pigs fly." It is a common expression, and I haven't heard the other variations you mentioned. I am not saying they do not exist, or that they are not valid. Perhaps they are used in Australia or in other parts of the English-speaking world. In the U.S., at least, it seems as though the expression has changed a bit over the last century and a half. The first time I ever heard "when pigs fly" as a child was on a popular sit-com called "Alice." A character on the program (a waitress named Flo) used to say it all the time. If I can find a clip on YouTube, I will post it for you as her way of speaking was quite funny.

Thank you, Mai, for your help.

Mai Mowafy Aug 9, 2012:

Thanks a lot Amal. Yes I am sure that the expression is used as such "when pigs fly" in America as I read in an American Dictionary of Idioms. Best of luck :)

Arabic & More (asker) Aug 9, 2012:

@rabbas Just wanted to confirm that the expression is definitely "when pigs fly" in U.S. English. It may be different in Australia.