AUC PHILOLOGICA
AUC PHILOLOGICA

AUC Philologica (Acta Universitatis Carolinae Philologica) is an academic journal published by Charles University. It publishes scholarly articles in a large number of disciplines (English, German, Greek and Latin, Oriental, Romance and Slavonic studies, as well as in phonetics and translation studies), both on linguistic and on literary and cultural topics. Apart from articles it publishes reviews of new academic books or special issues of academic journals.

The journal is indexed in CEEOL, DOAJ, EBSCO, and ERIH PLUS.

AUC PHILOLOGICA, Vol 2017 No 3 (2017), 19–34

Voice disguise strategies in Czech male speakers

Alžběta Růžičková, Radek Skarnitzl

DOI: https://doi.org/10.14712/24646830.2017.30
published online: 01. 09. 2017

abstract

Voice comparison in forensic phonetic casework requires the assessment of the similarity of the target voices. This task may be impeded by the speakers’ attempt to disguise their voice. The objective of this study is to map the strategies of voice disguise as employed by 100 native speakers of Common Czech. In agreement with findings in other languages, changes in speaking fundamental frequency appeared in most speakers, and phonatory modifications were the second most frequent type of disguise. Other strategies included modifications of the resonance characteristics of the voice, melodic and temporal changes. Recognition difficulty and naturalness of the disguise were also assessed. In addition, several acoustic parameters in the natural and disguised condition were compared in 15 speakers whose disguise rendered recognition more difficult.

keywords: voice; voice disguise; forensic phonetics; speaker identification; Czech

references (33)

1. Bartle, A. & Dellwo, V. (2015). Auditory speaker discrimination by forensic phoneticians and naive listeners in voiced and whispered speech. The International Journal of Speech, Language and the Law, 22, pp. 229–248. CrossRef

2. Boersma, P. (1993). Accurate short-term analysis of the fundamental frequency and the harmonics-to-noise ratio of a sampled sound. IFA Proceedings, 17, pp. 97–110.

3. Boersma, P. & Weenink, D. (2015). Praat: doing phonetics by computer (Version 6.0). Retrieved from http://www.praat.org.

4. Braun, A. (2006). Stimmverstellung und Stimmenimitation in der forensischen Sprechererkennung. In: Kopfermann, T. (Ed.), Das Phänomen Stimme: Imitation und Identität, pp. 177–181. Röhrig: St. Ingbert.

5. Chromý, J. (2014). Demokratizace spisovné češtiny a ideologie jazykové kultury po roce 1948 [The democratization of Standard Czech and the ideology of language culture after 1948]. Acta Universitatis Carolinae – Philologica, 3, pp. 71–81.

6. Clark, J. & Foulkes, P. (2007). Identification of voices in electronically disguised speech. The International Journal of Speech, Language and the Law, 14, pp. 195–221.

7. Eriksson, A. (2010). The Disguised Voice: Imitating Accents or Speech Styles and Impersonating Individuals. In: Llamas, C. & Watt, D. (Eds.), Language and Identities, pp. 86–96. Edinburgh: Edinburgh University Press.

8. Figueiredo, R. M. & Britto, H. S. (1996). A report on the acoustic effects of one type of disguise. Forensic Linguistics, 3, pp. 168–175.

9. Fox, J. (2003). Effect displays in R for generalised linear models. Journal of Statistical Software, 8(15), pp. 1–27. CrossRef

10. Hirson, A. & Duckworth, M. (1995). Forensic implications of vocal creak as voice disguise. In: BEIPHOL 64, Studies in Forensic Phonetics, pp. 67–76.

11. Krčmová, M. (2005). Stratifikace současné češtiny [Stratification of contemporary Czech]. Linguistica Online. Retrieved from http://www.phil.muni.cz/linguistica/art/krcmova/krc-012.pdf.

12. Künzel, H. J. (2000). Effects of voice disguise on speaking fundamental frequency. Forensic Linguistics, 7, pp. 149–179.

13. Laver, J. (1980). The Phonetic Description of Voice Quality. Cambridge: Cambridge University Press.

14. Lindh, J. & Eriksson, A. (2007). Robustness of long time measures of fundamental frequency. In: Proceedings of Interspeech 2007, pp. 2025–2028.

15. Masthoff, H. (1996). A report on a voice disguise experiment. Forensic Linguistics, 3, pp. 160–167.

16. Neuhauser, S. (2008). Voice disguise using a foreign accent: phonetic and linguistic variation. The International Journal of Speech, Language and the Law, 15, pp. 131–159.

17. Neuhauser, S. & Simpson, A. P. (2007). Imitated or authentic? Listeners' judgements of foreign accents. In: Proceedings of 16th ICPhS, pp. 1805–1808.

18. Nolan, F. & Grigoras, C. (2005). A case for formant analysis in forensic speaker identification. International Journal of Speech, Language and the Law, 12, pp. 143–173. CrossRef

19. Nolan, F., McDougall, K., De Jong, G. & Hudson, T. (2009). The DyViS database: style-controlled recordings of 100 homogeneous speakers for forensic phonetic research. International Journal of Speech, Language and the Law, 16, pp. 31–57.

20. Orchard, T. L. & Yarmey, A. D. (1995). The Effects of Whispers, Voice-Sample Duration, and Voice Distinctiveness on Criminal Speaker Identification. Applied Cognitive Psychology, 9, pp. 249–260. CrossRef

21. Perrot, P., Aversano, G. & Chollet, G. (2007). Voice disguise and automatic detection: review and perspectives. In: Stylianou, Y., Faundez-Zanny, M. & Esposito, A. (Eds.), Workshop on Nonlinear Speech Processing 2005, LNCS 4391, pp. 101–117. Berlin: Springer Verlag. CrossRef

22. Pollák, P., Volín, J. & Skarnitzl, R. (2007). HMM-based phonetic segmentation in Praat environment. In: Proceedings of the XIIth International Conference "Speech and computer – SPECOM 2007", pp. 537–541.

23. R Core Team (2015). R: A language and environment for statistical computing (version 3.2.2). R Foundation for Statistical Computing, Vienna. Retrieved from http://www.R-project.org.

24. Skarnitzl, R. (2011). Znělostní kontrast nejen v češtině [Voicing Contrast Not Only in Czech]. Praha: Epocha.

25. Skarnitzl, R. (2016). Co dokáže náš hlas? Fonetický pohled na variabilitu řečové produkce [What is our voice capable of? Phonetic perspective on the variability of speech production]. Slovo a smysl, 26, pp. 95–113.

26. Skarnitzl, R. & Hývlová, D. (2014). Statistický popis hodnot základní frekvence [Statistical description of fundamental frequency values]. In: Skarnitzl, R. (Ed.), Fonetická identifikace mluvčího [Phonetic Speaker Identification], pp. 49–64. Praha: Faculty of Arts, Charles University in Prague.

27. Skarnitzl, R. & Machač, P. (2010). Domain-initial coordination of phonation and articulation in Czech radio speech. Acta Universitatis Carolinae – Philologica, 1/2009, pp. 21–35.

28. Skarnitzl, R. & Vaňková, J. (this volume). Fundamental frequency statistics for male speakers of Common Czech. Acta Universitatis Carolinae – Philologica, 3, pp. X–Y.

29. Svobodová, M. & Voříšek, L. (2014). Identifikace mluvčích z pohledu autentické kriminalistické praxe v České republice [Speaker identification from the perspective authentic criminological practice in the Czech Republic]. In: Skarnitzl, R. (Ed.), Fonetická identifikace mluvčího [Phonetic Speaker Identification], pp. 136–144. Praha: Faculty of Arts, Charles University.

30. Vyhnálková, L. (2013). Vliv vzdělání na schopnost maskovat svůj hlas [The Effect of Education on the Ability to Disguise One's Voice]. Unpublished diploma thesis. Prague: Institute of Phonetics, Faculty of Arts, Charles University.

31. Wagner, I. & Köster, O. (1999). Perceptual recognition of familiar voices using falsetto as a type of voice disguise. In: Proceedings of 14th ICPhS, pp. 1381–1384.

32. Wickham, H. (2009). ggplot2: Elegant Graphics for Data Analysis. New York: Springer-Verlag. CrossRef

33. Yumoto, E., Gould, W. J. & Baer, T. (1982). Harmonics-to-Noise Ratio as an index of the degree of hoarseness. Journal of the Acoustical Society of America, 71, pp. 1544–1549. CrossRef

Creative Commons License
Voice disguise strategies in Czech male speakers is licensed under a Creative Commons Attribution 4.0 International License.

230 x 157 mm
periodicity: 3 x per year
print price: 150 czk
ISSN: 0567-8269
E-ISSN: 2464-6830

Download