Some often-overlooked uses of linguistics - 1
Firstly, anyone studying syntax and semantics will quickly encounter the concepts of ambiguity (how many ways can you read "Time flies like an arrow"?) and presupposition, and will come out of these classes much better-equipped to spot them. Which is an incredibly useful skill for keeping oneself informed. I'll talk a little bit more about presupposition, because I find it a lot more interesting.
Consider a scenario in which you and your companion see two sleeping dogs, that look more or less identical, and with which you have no prior acquaintance. Saying "the dogs are sleeping" will get you a nod in response. So will "the two dogs are sleeping". What about "the dog is sleeping"? You'll probably get a weird look and the question, "Which dog?" Your friend will assume that one of the dogs is more contextually-relevant than the other for you for some reason, or perhaps that you're referring to a completely different dog altogether - but again, you'll first have had to establish the context in which that different dog was relevant. Now, suppose you said something like "the three dogs are sleeping". Your friend will probably think that you can't count. Because if you say "the X" in a statement in which you're not overtly negating the existence of X (i.e. "the X doesn't exist"), you are basically presupposing that there is one and only one contextually-relevant X, before making a statement about that X. (You can extrapolate this to "the Xes" and "the N Xes" quite easily.)
Presupposition is not something that only alert linguists can spot. All of us derive presuppositional inferences from statements such as "the X". It's just that a lot of people do this subconsciously, not consciously. It's only when the presupposition is exceptional in some way (very negative, for example) that we sit up and take notice, as in the famous question "Do you still beat your wife?" You can't answer "yes" or "no" to that without implicating yourself in a crime of abuse. You have to actively dispute the presupposition by saying, "I've never beaten my wife, and I don't beat her now!'
All definite determiners, including possessors, create this presuppositional inference. When George W. Bush refers to "Saddam's weapons of mass destruction" in a non-negative context, he is unconsciously creating the inference that those weapons of mass destruction exist. I suspect that if you look at his speeches, even the recent ones in which he seeks to distance himself from the flawed intelligence that led to the Iraq war, you'll find that he still says phrases like "the WMDs" and "Iraq's WMDs". (If I find the time to look up his speeches, and find evidence of this, I'll be sure to post it.)
Whew! That was a long spiel about presupposition. I'll write about the second skill in the next post.