Kaori Idemaru was a middle schooler living in the Japanese countryside when she discovered that learning a foreign language—English, in her case—could open a portal to a new world.

Today, Idemaru studies how speech is learned and perceived. Her findings contribute to a range of linguistic fields, including language acquisition and processing, cognitive functioning, cultural understanding, and identity—that is, how language reflects one’s class, region, and even gender.

In a novel project with Professor Lori Holt of Carnegie Mellon University, Idemaru tested listeners’ recognition of the words “beer,” “pier,” “deer,” and “tear” when hearing an artificial accent. The researchers found that the human brain, in recognizing closely related words, picks and chooses from various acoustic properties such as pitch and the pronunciation of consonants; it effectively acts like an equalizer, giving more (or less) weight to whichever property will aid recognition.

The researchers deemed this cognitive flexibility “dimension-based statistical learning”: the brain sifts through different acoustic properties to recognize a word despite fluctuations caused by accent and other factors. Idemaru is expanding on this research with University of Oregon colleagues Charlotte Vaughn and Volya Kapatsinski.

“When we perceive speech sounds, we’re actually using multiple acoustic properties,” Idemaru says. “But the weight we give to those properties isn’t fixed; some people don’t use pitch to perceive words, and some people overuse pitch, but we get accustomed to how speakers vary in those acoustic dimensions. We have really fine-grained perceptual strategies to understand the language we’re hearing.”

Tone it up

In a project with fellow UO researchers Peipei Wei and Lucy Gubbins, Idemaru explored language characteristics that can lead to perceptions that one is speaking with a foreign accent. In their examination of English- and Mandarin Chinese-speaking subjects using Japanese, the team found that tone—the use of pitch—reliably predicted the degree of accent in speaking a foreign language.

We’re all in this together

Idemaru won a Remote Teaching Award for converting a course on Japanese phonetics and pronunciation to the online world so students could participate remotely during the pandemic.

One fun find: use of the online word processor Google Docs, which made it easier for all students—and particularly the quieter ones—to participate simultaneously but anonymously, everyone examining the same language exercise, concurrently. “Seeing 18 cursors moving at the same time made it fun for all of us,” Idemaru says. “Students were more comfortable providing written responses inthis format.”

The universal language of “treat”

Away from the classroom, Idemaru jokes she can usually be found acting as “humble human servant” to Rosie, her 13-year-old Cavalier King Charles Spaniel.

“She has trained me quite well,” Idemaru says, laughing. “She’s a frequent visitor to Friendly Hall. There used to be pots of treats in different offices and she would make the rounds—she knew which doors were the good doors. She would sit in front of a door and wait for it to open and refuse to go home.”