Noam Chomsky: Deepest Property of Language

What are the most beautiful or fascinating aspects of language or ideas in linguistics or cognitive science that you've seen in a lifetime of studying language and studying the human mind? Well, I think the deepest property of language and puzzling property that's been discovered is what is sometimes called structure dependence. We now understand it pretty well, but it was puzzling for a long time. I'll give you a concrete example. So suppose you say, the guy who fixed the car carefully packed his tools. It's ambiguous. He could fix the car carefully or carefully pack his tools. Suppose you put carefully in front, carefully the guy who fixed the car packed his tools. Then it's carefully packed, not carefully fixed. And in fact, you do that even if it makes no sense. So suppose you say carefully, the guy who fixed the car is tall. You have to interpret it as carefully he's tall, even though that doesn't make any sense. And notice that that's a very puzzling fact, because you're relating carefully, not to the linearly closest verb, but to the linearly more remote verb. Linear closeness is an easy computation. But here you're doing a much more, what looks like a more complex computation. You're doing something that's taking you essentially to the more remote thing. If you look at the actual structure of the sentence, where the phrases are and so on, turns out you're picking out the structurally closest thing, but the linearly more remote thing. But notice that what's linear is 100% of what you hear. You never hear structure. So what you're doing is, and incidentally this is universal, all constructions, all languages. And what we're compelled to do is carry out what looks like the more complex computation on material that we never hear. And we ignore 100% of what we hear and the simplest computation. By now there's even a neural basis for this that's somewhat understood. And there's good theories by now that explain why it's true. It's a deep insight into the surprising nature of language with many consequences.