Finding meaning behind the words
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Modern versions continue to improve on the traditional technique of forcing users to speak in a slow, consistent tone, but software that continues to force users to adapt their speech to the computer’s requirements, rather than the other way around, does not result in the speedy adoption of the technology. Scientists want people to be able to speak to computers in the same way that they would talk to another human being.

Spoken words contain important clues about their meaning, such as their location in a sentence. They’re going to their house over there or homonyms like karat, caret and carrot are good examples of ways in which identical sounds can carry different meanings, depending on context.

“There is a great deal of importance in how you say something versus what you say,” says Mari Ostendorf, a professor of electrical engineering at the University of Washington. One of her research projects aims to develop systems that can locate the invisible punctuation in speech and use it to help determine meaning. Paragraphs, commas and question marks are all basic elements of the written word, but their location in a spoken sentence can be difficult to discern. “We also need to be able to detect emotion and stress,” she says.

Researchers believe that the best way to find and incorporate meaning is by using increasingly powerful computers to simultaneously detect and record more variables in speech. “The number of neurons in the brain devoted to speech is far more than the number of parameters in software,” Juang says.

Perhaps the most significant way to improve current software is with an increase in computing power, says Bishnu Atal, also at the University of Washington. Current technology analyzes approximately 20 or 30 features in speech every few milliseconds but researchers hypothesize that software may need to analyze several thousand features every few milliseconds to gather enough information about speech to determine meaning. The best way to accomplish this is by using more powerful computers.