The Effects of Forensically Relevant Face Coverings on the Acoustic Properties of Fricatives

Abstract

This forensically motivated study investigates the effects of a motorcycle helmet, balaclava, and plastic mask on the acoustics of three English non-sibilant fricatives, /f/, /θ/, and /v/ in two individuals. It examines variation within the individual as an effect of the physical environment. Two speakers recorded a list of minimal pairs in each of the three guises and with no face covering. The results showed that facewear significantly affected fricative intensity and the four spectral moments: centre of gravity, standard deviation, skewness, and kurtosis. The acoustic changes caused by facewear have implications for judging the reliability of earwitnesses’ content recall and voice identification as well as forensic speech scientists’ examination of content and speaker identity in disputed recordings.

Keywords

• intraspeaker variation
• sociophonetics
• uk english
• forensic linguistics