In which I offer a minor cultural tidbit...

In most Southeast Asian languages, polite speaking requires that you put an honorific at the end of many phrases, which depends only on the sex of the speaker. For example, in Thai, a man would say "Thank you, krep" and a woman "Thank you, kaa" - regardless of who's listening.

Now that they're learning English, my most scrupulously polite students have carried this habit with them into their new language. As a result, many male students are refering to everyone as "Sir" - both male and female. The female students, predictably, are calling everyone "Ma'am" with a similar disregard for the sex of the listener.

It is proving very difficult to break them of this habit.