Speaker-individuality in Fujisaki model f0 features: implications for forensic voice comparison

Fundamental frequency (f0) is a highly speaker-specific feature. Consequently, practitioners often use f0 information in forensic casework. Current research principally examines the use of long-term f0 statistics such as f0 means and standard deviations for forensic voice comparison. The present study investigates how short-term f0 features such as measured by the Fujisaki intonation model capture speaker-individuality. Based on data of a homogeneous group of Zurich German speakers, we conducted an experiment on a large corpus of read speech and on a subset of sentences that included speaking style variability (spontaneous vs. read). The latter is characteristic of forensic casework. Speakers demonstrated high between-speaker variability and low within-speaker variability across the two speaking styles for a number of f0 features. Given this evidence of speaker-individuality, we discuss Fujisaki f0 features’ potential for forensic voice comparison.