Conundrums and befudlements

I may have blogged about this before, but if I have the answer still hasn't been brought to my attention. Why does the English language refer to trousers as a PAIR of pants (plural)? At some point in our history was there a singular pant that only covered one leg? How come shirts get a singular term? They cover 2 arms? Pants are a singular item. They can not be split into 2, like say.. a pair of shoes. I can throw a singular shoe at you, but I cannot through a pant at you. I think this is unfair to pants. Pants are getting a bad rap because of the shortcomings of our language.
The same problem exists with all leg wear that isn't female based (dress, skirt, etc.)
I realize these items provide arguments based on holes. A skirt or dress has one individual enclosure for both legs, where a pair of pants has 2. So why isn't it a pant with a pair of pant legs instead of a pair of pants with a pair of pant legs.
English is a silly language some times.