says Sharon Oviatt, an experimental psychologist at the university's OGI School of Science & Engineering. "We discovered that people subconsciously tailor their voice to the computer's THE CRITICAL LAST INCH-INPUT AND OUTPUT TECHNOLOGIES voice. So, for example, if the computer voice is talking more quietly, the person interacting with the computer will talk more quietly. This is a major new source of variability in users' spoken language to computers, which is opening up new scientific directions for mobile audio interface design." To study the phenomenon, Oviatt and her graduate students asked students ages 7 to 10 to use a special handheld computer to talk with a variety of digital marine animals. The students used the computer to speak directly to the ani- mated software characters. The marine animals answered each question using text-to-speech (TTS) output, along with animated movement. Four different TTS voices were used to determine whether the children accommodated their own voices-including amplitude, duration, and pitch- to more closely match the TTS output from the computer characters. Oviatt and her team are now modeling the results from these and future experiments SO they'll be able to reliably predict how speech will vary under certain cir- cumstances. Such quantitative modeling, Oviatt says, will lead to a new science of audio interface design, which will be important for developing new mobile systems that are capable of processing users' speech reliably in natural set- tings. "Ideally, we want to develop high-functioning applications and interface designs for specialized populations," says Oviatt. "This is a tall order for com- puters right now." Humans presently must adapt to the limitations of computers, but future computers need to be more adaptive to people. "They should be smaller and embedded SO we don't have to carry them," Oviatt notes. "They should be able to combine pen and speech input to express themselves naturally and efficiently and with information tailored to an individual's commu