Protecting speech privacy from native/non-native listeners - effect of masker type

Abstract

Sound masking is a technique used for protecting speech confidentiality, which is realised by adding maskers to cover target speech. Numerous research have demonstrated the native and non-native differences in perceiving masked speech, but few have compared the effect of masker types from the perspective of effectiveness of speech privacy. This paper reports on the result of an English word identification task by native and non-native listeners where five types of maskers are implemented. Natives, non-natives residing in English-speaking country, and non-natives residing in Japan were tasked to write down sentences when masking sound was present. Results showed that while the three groups of listeners’ baseline performance differed significantly, no significant difference was observed between two groups of non-native listeners in the presence of maskers. Additionally, five types of maskers impacted native and non-native listeners differently, which provides novel evidence on future implementation of maskers to increase speech privacy.