By MARY COCHRANE
Contributing Editor

You are reading an article, a book or the newspaper, and you come across a word you don't recognize. What do you do?

"It's something people do all the time," says William Rapaport, associate professor of computer science in the School of Engineering and Applied Sciences.

"You come across a word you don't know, you decide if you want to understand the passage, you need to understand what the word means, but it's either not in the dictionary or you are too lazy to look it up. Or you go to look it up and you can't understand the meaning from the dictionary anyway and there's nobody around to ask."

That's why Rapaport and colleague Michael Kibby, professor of learning and instruction in the Graduate School of Education, have spent years researching a concept called contextual vocabulary acquisition, or CVA, which readers can use to figure out meanings of unfamiliar terms. Now the pair plans to turn its findings into a curriculum designed to improve reading skills for students nationwide.

CVA—using clues in the text surrounding an unknown word to discover its meaning—is "not a once-in-a-while thing," but a commonly practiced technique, Rapaport says.

"Most of our vocabulary—around 90 percent—is acquired this way: People know the meanings of more words than they are explicitly taught, so they must have learned most of them as a byproduct of reading or listening," according to Rapaport.

But socioeconomic class has "a huge impact" on how many words a person will learn, Kibby says. Studies show young children of professional parents hear an average of 47 million words, as opposed to welfare homes, where those children hear just 11 million words.

"We believe there needs to be a constant barrage of words in school," Kibby adds. "Teachers need to make words of primary importance. I used to think teaching reading is the most important thing in the world. In the last 10 years, I've changed to thinking that teaching the words of the language is the most important thing we can do for students."

Current reading methods are either "quite vague" or seriously flawed when it comes to teaching vocabulary, according to Kibby and Rapaport.

"One of the strategies that I like to make fun of goes as follows: Step one, figure out the part of speech of the unknown word. Step two, look at the grammatical structure of the sentence. Step three, look at the surrounding text to find information that might give you spatial or temporal information, whatever other clues you can find. And step four of this strategy is 'guess.' When I tell this to computer scientists, they all burst out loud laughing. You can't have a computer program guess without telling it how," Rapaport says.

To refine their CVA computer program, Rapaport and Kibby used "think-aloud verbal protocols" to see how advanced readers use reasoning and other cognitive processes, and how they apply their "prior," or personal, background knowledge to define unknown words.

One think-aloud exercise involves a scene from Sir Thomas Malory's "Le Morte d'Arthur," a novel about King Arthur, which begins: "Right so as they sat, there came a white hart running into the hall with a white brachet next to him."

Using CVA, readers can look for clues about what "brachet" means in subsequent text, such as the next sentence "The hart went running about the Round Table...the white brachet bit him." Most readers will correctly assume from this sentence that the brachet is a living creature, and then will read "the knight arose, took up the brachet, went forth out of the hall" to discover the brachet is a smallish animal.

The final clues appear in the sentences "the white brachet...bayed at him" and "a brachet...and other hounds came behind," revealing the brachet to be a dog.

Kibby and Rapaport are not alone in their plan to improve schoolchildren's vocabulary and reading scores. The National Assessment of Educational Progress (NAEP) has developed a new reading assessment to begin in 2009, and Kibby, who served on the committee that completed the framework of the new assessment, is working with another committee to create the test questions for the vocabulary segment.

The timing, he adds, couldn't be better.

"If students don't have a strong vocabulary, if they don't know what words mean, they won't know what things are, how things move around, where they fit in the world, and this results in a tremendous amount of ignorance that is very hard to overcome," Kibby says.