One woman can make you fly like an eagle, another can give you the strength of a lion, but only one in the cycle of life can fill your heart with wonder and the wisdom that you have known a singular joy. I wrote that for my girlfriend.
Letters are symbols. They are building blocks of words which form our languages. Languages help us communicate. Even with complicated languages used by intelligent people, misunderstanding is a common occurrence.
Just cos they are aliens, does not mean they do not have to visit the little boys room. Although they probably do something weird and alienesque, like it comes out of the top of their heads or something.