The thing with the "redefining" arguement is this. Words do mean things, as I have told my nephew time and again as he calls people on Xbox Live "gay" as an insult. Words have specific meanings, and one needs to keep their meaning in mind before flinging them around casually. When my nephew tries to claim that he is not insulting gay people, just using the word "gay" to mean "bad and stupid," I point out that there is no dictionary in the world that defines "gay" that way. In modern usage, "gay" generally means "homosexual."
That's the thing, though. In modern usage. Gay used to be a word that mean "happy," or, "merry." "Queer" used to mean "strange." And yet, today, if I refer to someone as gay or queer, no one assumes I mean they are happy or odd. Yes, somehow, by some inconcievable process called the EVOLUTION OF LANGUAGE, the accepted definition of these words changed. Not only this, but these changes came about within cultural memory. In the Fifties, if I were to refer to my friend as "both gay and queer," a listener might think I was referring to a merry eccentric (which, to be fair, most of my gay friends are, but so are most of my straight friends). Just twenty years later, in the Seventies, if I were to refer to my friend the exact same way, I would be being redundant, and maybe a little offensive, as this was before the gay community reclaimed the word "queer." So the meanings of the words "gay" and "queer" changed, and look! Society hasn't collapsed! Maybe because taking words and verb tenses and conjugations and sentence construction from other languages and distorting it so that it's barely recognizable is what the English language has been widely know for SINCE ITS INCEPTION!
So why, WHY all the panic about redefining the word "marriage" to include same-sex couples? Why are some people so worried about changing the meaning of this ONE WORD when there is almost certainly not a single other word in the English language that remains precisely true to its original definition? Is it, perhaps, their favorite word? Do they not know that language evolves over time, due to maybe never having read any Shakespeare, or even Victorian literature, or ever having heard someone speak until they were fully-fledged adults?
Or maybe, just maybe, it's not about the word after all.