Here's an interesting little bit of language history that I happened upon the other day, involving silent letters.
I've always been kind of amused at the fact that you don't pronounce the "h" in ghost. It's kind of funny, if you think about it. It's there... but you never hear it, and no one dare say it... Oooooo. Anyway, why is that pesky letter there?
People were writing long before the dictionary existed. Mostly it was the monks who did the copying and writing of books, and pretty much everyone wrote words however they felt they should be spelled. Likewise, the printing press existed before the dictionary, and we ended up in the same situation. Lots of people from all different kinds of backgrounds were printing in the English language, but bits of their own heritage were filtering in to the mix.
The word ghost was originally spelled without the "h," nice and phonetically. But printers from Holland tossed an "h" in there because that's how they spelled it, and for some reason, it stuck.
Interestingly enough, the printers weren't only tossing in letters because of cultural differences. They also liked nice straight lines (who can blame them?) and so if they had to knock an extra letter off of a word or two in order to get a nice, tidy justification, they'd go for it. Words like, logic, magic, and music used to have a "k" at the end, but they got nicked.
In 1755 Samuel Johnson had enough of arbitrary spelling, and made the first English Dictionary. Shortly after the American Revolution, Noah Webster waged his own kind of war against the English by writing an American Dictionary, in which he knocked the "u" out of words like color, flavor and honor.
How do I know all this? Well, it's because I read books. Most of this stuff was news to me, I learned it from THE WORD SNOOP by Ursula Duborsarsky. If you're as big of a nerd as I am, you might want to check it out.