Do long-term acoustic-phonetic features and mel-frequency cepstral coefficients provide complementary speaker-specific information for forensic voice comparison?

A growing number of studies in forensic voice comparison have explored how elements of phonetic analysis and automatic speaker recognition systems may be integrated for optimal speaker discrimination performance. However, few studies have investigated the evidential value of long-term speech features using forensically-relevant speech data. This paper reports an empirical validation study that assesses the evidential strength of the following long-term features: fundamental frequency (F0), formant distributions, laryngeal voice quality, mel-frequency cepstral coefficients (MFCCs), and combinations thereof.

Modeling Lexical Tones for Speaker Discrimination.

Fundamental frequency (F0) has been widely studied and used in the context of speaker discrimination and forensic voice comparison casework, but most previous studies focused on long-term F0 statistics. Lexical tone, the linguistically structured and dynamic aspects of F0, has received much less research attention. A main methodological issue lies on how tonal F0 should be parameterized for the best speaker discrimination performance.

Evidential value of voice quality acoustics in forensic voice comparison.

Voice recordings in forensic voice comparison casework typically involve speech style mismatch and are separated by days or weeks, but studies that aim to empirically validate the evidential value of speech features rarely include systematic comparisons on contemporaneous vs. non-contemporaneous recordings and match vs. mismatch in speech style.