As a graduate student, I took courses from UC Berkeley's Professor Charles (Chuck) Fillmore, one of the world's greatest linguists. Prof. Fillmore's specialty is the interrelationship between meaning and the structure of language, and his FrameNet project is building a high-quality, immensely valuable computational linguistics resource. When he lectures, Prof. Filmore has a very sweet, understated style, so I'm always surprised by his manner when he discusses language topics related to violent themes; the best description is: "with relish". I still remember an example he gave in class one day when he was illustrating the difference between count nouns and mass nouns in English. Count nouns refer to nouns that are individual objects with precise boundaries, like trees, houses, cats. Mass nouns (also known as uncountable nouns) often refer to things that do not have well-defined boundaries and are not easily identified as discrete entities: "surf", "traffic", and "electricity" are examples. In English, we indicate the difference between a mass noun and a count noun by the words we put in front of them. You can't have three traffics or four electricities. And you can't say "Give me cup." without a preceding article (such as "a" or "the"). Some words fall into both categories, depending on how you think about them. Sand in aggregate is a mass noun, but you can look at individual grains of sand as well. It's the usage of the word that is key. In English we have to use three words to indicate the count version of sand ("grain of sand") and just one for the mass version. Mass nouns can also refer to groups of count nouns, as in "furniture" and "poultry". Which leads me to Prof. Fillmore's illustrative and memorable example of mass versus count nouns. He noted the difference between saying "There are cats all over the driveway." and "There is cat all over the driveway." The second sentence suggests that something awful has happened, turning the cat from a count into a big mass. And he said it with a twinkle in his eye.

-Marti Hearst

*Editor's Note: Marti is a professor at Berkeley in the very cool School of Information and a consultant at Powerset. All opinions expressed are more or less hers. When she's inspired by a cool feature of language, she'll blog it here.*