Automatic speaker recognition of spanish siblings: (monozygotic and dizygotic) twins and non-twin brothers


  • Eugenia San Segundo Department of Linguistics and Language Science, University of York
  • Hermann Künzel Department of Phonetics, University of Marburg



forensic phonetics, twins, siblings, automatic speaker recognition, Spanish


The performance of the automatic speaker recognition (ASR) system BatvoxTM (Version 4.1) has been tested with a male population of 24 monozygotic (MZ) twins, 10 dizygotic (DZ) twins, 8 non-twin siblings and 12 unrelated speakers (aged 18–52 with Standard Peninsular Spanish as their mother tongue). Since the cepstral features in which this ASR system is based depend largely on anatomical–physiological foundations, we hypothesized that such features ought to be gene-dependent. Therefore, higher similarity values should be found in MZ twins (100% shared genes) than in DZ twins, in brothers (B) or in a reference population of unrelated speakers (US). Results corroborated the expected decreasing scale MZ > DZ > B > US since the similarity coefficients yielded by the automatic system for these speakers decreased exactly in the same direction as the kinship degree of the four speaker groups diminishes. This suggests that the system features are to a great extent genetically conditioned and that they are hence useful and robust for comparing speech samples of known and unknown origin, as found in legal cases. Furthermore, the 9.9% EER (Equal Error Rate) obtained when testing MZ pairs lies around the same value (11% EER) found in Künzel (2010) with German twins.


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How to Cite

San Segundo, E., & Künzel H. (2015). Automatic speaker recognition of spanish siblings: (monozygotic and dizygotic) twins and non-twin brothers. Loquens, 2(2), e021.