The Effects of Acoustic and Semantic Enhancements on Perception of Native and Non-Native Speech

Previous research has shown that native listeners benefit from clearly produced speech, as well as from predictable semantic context when these enhancements are delivered in native speech. However, it is unclear whether native listeners benefit from acoustic and semantic enhancements differently when listening to other varieties of speech, including non-native speech. The current study examines to what extent native English listeners benefit from acoustic and semantic cues present in native and non-native English speech. Native English listeners transcribed sentence final words that were of different levels of semantic predictability, produced in plain- or clear-speaking styles by Native English talkers and by native Mandarin talkers of higher- and lower-proficiency in English. The perception results demonstrated that listeners benefited from semantic cues in higher- and lower-proficiency talkers' speech (i.e., transcribed speech more accurately), but not from acoustic cues, even though higher-proficiency talkers did make substantial acoustic enhancements from plain to clear speech. The current results suggest that native listeners benefit more robustly from semantic cues than from acoustic cues when those cues are embedded in non-native speech.