Non-native talkers and listeners and perceptual benefits of clear speech

Abstract

Native clear speech aids speech perception for various native populations such as hearing-impaired adults (Picheny et al., 1985). Compared to native speech, little is known about the benefit of non-native clear speech (Smijlanic and Bradlow, 2011). The current study investigates whether non-native clear speech can aid both native and non-native listeners, using every combination of talkers and listeners (native talker/listener, and non-native talker/listener). Non-native participants were L1 Korean speakers, while native participants were L1 American English speakers. Each group had 32 participants listening to semantically anomalous English sentences recorded by four native and four non-native talkers and presented with speech-shaped noise at 0 dB SNR in each speaking style (casual and clear). Each sentence had four keywords, and the number of correct keywords was converted to rationalized arcsine units. The results show significant effects of talker L1, listener L1, and speaking style. Native speech was more intelligible than non-native one and native listeners outperformed non-native listeners. Clear speech was more intelligible than casual speech. However, none of the interactions among the factors reached statistical significance, indicating the two groups of talkers and the two groups of listeners behaved in a parallel way in terms of producing and receiving clear speech benefits.