Speech unmasked
UWM linguist studies how masks impact intelligibility
Wearing a mask is one of the most effective ways to prevent the spread of the coronavirus, but there’s no question that masks make it harder to understand what people are saying. Or that’s been the thought, anyway. UWM associate professor of linguistics Anne Pycha is the coauthor of a new study published in the journal Cognition that examined how well people can understand the speech of speakers wearing face masks. With Wisconsin and other states across the nation under a mask mandate to prevent the spread of the coronavirus, Pycha and her coauthors, Michelle Cohn and Georgia Zellou of the University of California-Davis, realized they had a golden opportunity. “Because we all wear face masks, the basic circumstances under which we produce and perceive speech have fundamentally changed,” Pycha explained. “We’ve all of a sudden got this barrier on our mouths that impacts how we speak. … Once we started thinking along those lines, we realized that the face masks presented a really interesting test case for researchers like us.” Experimenting with speech As it happens, Pycha said, humans are actually very good at communicating. In addition to signals like facial expressions and body cues, people naturally modulate their speech to reflect their environment – speaking louder in a crowded room, for example. She and her coauthors wondered: How do masks interfere with our speech? And can speakers overcome this new barrier to communication? To test that question, Pycha, Cohn, and Zellou had two speakers, a man and a woman, record specific sentences both while wearing a fabric face mask and not wearing a mask. The sentences were pulled from a standardized list called the “Speech Perception in Noise” set. They asked the speakers to record the sentences in three ways: Speaking in a casual, conversational tone; speaking with positive emotion; and speaking clearly to someone who might have trouble understanding. 4 • IN FOCUS • March, 2021
To each recording, the researchers added a bit of background noise to mimic what a listener might hear if they were listening to speech in a casual environment. Listeners in the experiment had to hear the recordings and then type the last word of the sentence they heard. Then, Pycha Michelle Cohn and her colleagues examined their answers for accuracy. In the sentence, “Miss Brown is considering the coast,” for example, respondents would have to type “coast” to be considered accurate. Answering “toast” or any other word would be a mark against intelligibility. Surprising results
Georgia Zellou
Some of the results were exactly what you’d expect. “When people were speaking casually, it was more difficult for our listeners to understand. Intelligibility went down when the mask was on. We’ve all had that experience,” Pycha said. The same held true when people were speaking with positive emotion. But, when the speakers were told to “speak clearly,” things got interesting. “The listeners were actually better able to identify words when the speaker was wearing a mask compared to when they were not wearing one,” Pycha said. “It’s almost as if, when you ask people to speak clearly in a noisy situation, intelligibility goes up, but when you
