Stop shouting at me: Why clear speech can sound angry

"We often hear communication partners of individuals with hearing loss say that it seems that when they try to speak clearly, their partners think they are shouting at them," Morgan said.

Now a new study supports the idea that clear speech can indeed carry negative overtones even when the phrase itself is emotionally neutral. Morgan will present his team's results at the 167th Meeting of the Acoustical Society of America (ASA) in Providence, RI.

In the new experiment, 18 young adults with normal hearing listened to a set of conversational and clear sentences from the Ferguson Clear Speech Database. This database includes phrases spoken by volunteers under instructions to read sentences in two different styles: first as though they were having a normal conversation (their "conversational speech" style), and a second time as though they were talking to a person with hearing loss (their "clear speech" style). Each sentence included in this study was emotionally neutral, such as in "he picked up the bid and put it away" and "use the word 'bod' in a sentence."

The University of Utah team selected sentences from each speaking style as read by speakers who had previously been classified as having either a big difference between their two speaking styles (i.e., their clear speech was perceived as very distinct from their natural conversational speech) or a small difference (i.e., there was almost no perceived distinction between their clear and conversational speech). The 18 listeners were then asked to assign an emotion category to each sentence: anger, sadness, happiness, fear, disgust, or neutral (meaning no intended emotion).

Listeners thought the clear versions of the sentences from the database sounded angry more often and happy less often than the more natural conversational versions. Furthermore, the group of speakers who had the largest perceived distinctions between clear and conversational speech were judged to be more angry and less happy than those with smaller differences between the two styles. This suggests, Morgan said, that as a speaker begins to sound more clear, they also sound more angry and less happy.

Further work is needed to give scientists a better picture of the exact nature of the different relationships between speaking style and perceived emotion, Morgan said. However, he added that he feels that this study is a good start in helping to make audiologists aware of this potential problem.

"When we invite people to change how they speak to achieve some goal, like increased accuracy in speech understanding, we need to consider how those changes affect other perceived aspects of speech, like the emotional state of the speaker," Morgan said. "We could potentially begin searching for better ways to counsel patients and their communication partners to increase understanding without appearing angry or otherwise upset.

For example, future research may identify the acoustic differences between sentences that the listeners labeled "neutral" and those they labeled "angry." This work might be used to teach people how to speak clearly without conveying negative emotion.