Multiparametric Analysis of Speaking Fundamental Frequency in Genetically Related Speakers Using Different Speech Materials: Some Forensic Implications.

Julio Cesar Cavalcanti,Anders Eriksson,Plinio A Barbosa

doi:10.1016/j.jvoice.2021.08.013

Abstract

To assess the speaker-discriminatory potential of a set of fundamental frequency estimates in intraidentical twin pair comparisons and cross-pair comparisons (i.e., among all speakers). A total of 20 Brazilian Portuguese speakers of the same dialect, namely 10 male identical twin pairs aged between 19 and 35, were recruited. The participants were recorded directly through professional microphones while taking part in a spontaneous dialogue over mobile phones. Acoustic measurements were performed in connected speech samples, and in lengthened vowels, at least 160ms long produced during spontaneous speech. f0 baseline, central tendency, and extreme values were found mostly discriminatory in intra-twin pair and cross-pair comparisons. These were also the estimates displaying the largest effect sizes. Overall, only three identical twins were found statistically different regarding their f0 patterns in connected speech, but not for lengthened vowel-based f0 metrics. Estimates of f0 variation and modulation were found the least discriminatory across speakers, which may signal the control of speaking style and dialect on dynamic patterns of f0. Concerning system performance, the base value of f0 (f0 baseline) was found the most reliable metric, displaying the lowest equal error rate (EER). The outcomes suggest that, although identical twins were very closely related regarding their f0 patterns, some pairs could still be differentiated acoustically, only in connected speech. Such findings reinforce the relevance of analyzing long-term f0 metrics for speaker comparison purposes, with particular consideration to f0 baseline. Furthermore, f0 differences across subjects were suggested as more expressive in connected speech than in lengthened vowels.

Highlights

IntroductionThis study aimed at analyzing the speaker-discriminatory potential of a set of fundamental frequency descriptors in comparisons performed between genetically related (i.e., identical twin pairs) and cross-pair comparisons (i.e., among all speakers)
This study aimed at analyzing the speaker-discriminatory potential of a set of fundamental frequency descriptors in comparisons performed between genetically related and cross-pair comparisons
The inter-speaker comparisons were performed on the basis of two different kinds of speech material: intervals of continuous speech vs. lengthened vowels extracted from dialogues which were perceived, in most cases, as filled pauses

Summary

Introduction

This study aimed at analyzing the speaker-discriminatory potential of a set of fundamental frequency descriptors in comparisons performed between genetically related (i.e., identical twin pairs) and cross-pair comparisons (i.e., among all speakers). The analysis performed on the basis of spontaneous speech set out to verify which metrics are considered remarkably “individual” even across very similar speakers, as is the case with identical twins who grow up together. Such individuals represent the highest possible level of intersubject physical similarity and are, in most cases, exposed to very similar environmental and linguistic influences, which characterizes them as an optimal group for exploring idiosyncrasy or individuality in speech production. Differences in voice fundamental frequency (hereafter, f 0) average values and variability have been reported as a function of several components, ranging from physiological, psychological, linguistic, stylistic to socio-cultural factors.[1−10] The different levels of contribution of these components on the voice/speech fundamental frequency reveal the multimodal nature of such physical parameters, bearing repercussions on how individuals are perceived by listeners.[11]

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Discussion

Conclusion