Gender, pitch variability, speaking rate, and low-frequency modulation affect judgments of anger in clear speech

Clear speech, a speaking style used to communicate with individuals with hearing loss and other communication difficulties, has been shown to sound "angry" more often than conversational speech [Morgan and Ferguson (2017). J. Speech. Lang. Hear. Res. 60, 2271-2280]. In this study, acoustic analyses of emotionally neutral sentences from a database of 41 talkers spoken both clearly and conversationally were analyzed in tandem with judgments of emotions for the same sentences to assess potential acoustic correlates of judgments of anger in clear speech. Principal component analyses were conducted to guide the selection of acoustic measures for statistical models. Decreases in speaking rate and increases in temporal fluctuations in amplitude centered at 1 Hz, both of which are prominent features of clear speech, were both associated with increases in judgments of anger. Increases in fundamental frequency variability, another common feature of clear speech, were associated with increases in judgments of any amount of anger but only in conversational speech. Finally, after controlling for speaking style and fundamental frequency variability, women were judged to sound angry more often than men. The results suggest that speaking rate, amount of word or phrase-level amplitude modulation, and fundamental frequency variability could possibly be manipulated to decrease judgments of anger in clear speech.