A case for formant analysis in forensic speaker identification


  • Francis Nolan University of Cambridge
  • Catalin Grigoras




speaker identification, spectral analysis, formants, long-term averages, formant dynamics


Views differ on the relative importance for forensic speaker identification of different aspects of the speech signal. It is argued here that formants, whose frequencies and dynamics are the product of the interaction of an individual vocal tract with the idiosyncratic articulatory gestures needed to achieve linguistically agreed targets, are so central to speaker identity that they must play a pivotal role in speaker identification. As a practical demonstration a case is described in which F1, F2 analysis of a vowel and F2 analysis of three diphthongs show a consistent separation between two recordings, thus effectively eliminating a suspect from having made obscene telephone calls. Subsequent additional analysis, based on the statistical distribution of formant frequency estimates throughout the samples, confirms the distinctness of the voice of the suspect and that of the obscene caller. The theoretical foundation for several kinds of formant-based analysis is then discussed.

Author Biographies

Francis Nolan, University of Cambridge

Francis Nolan is Professor of Phonetics in the Linguistics Department at the University of Cambridge and a founding member of IAFPA.

Catalin Grigoras

Catalin Grigoras is a forensic expert at the National Institute of Forensic Expertise, Romania and assistant professor at the Rm Sarat Criminalistics School of Babes-Bolyai Law University.



How to Cite

Nolan, F., & Grigoras, C. (2005). A case for formant analysis in forensic speaker identification. International Journal of Speech, Language and the Law, 12(2), 143–173. https://doi.org/10.1558/sll.2005.12.2.143




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