In this talk, I will focus on a voice parameter that has been widely investigated in Forensic Phonetics, particularly in the past five years. This feature is called voice quality and it has two possible interpretations. In a narrow definition, it refers to the activity of the vocal folds only and it implies the acoustic analysis of sustained vowels. According to the broad definition, VQ results from a combination of long-term laryngeal and supralaryngeal features.
I will start by introducing what Forensic Phonetics is and its main areas of application, in order to gain some insight into the most common methods and parameters used in Forensic Speaker Comparison, a task that forensic phoneticians are frequently requested to do. This consists in comparing the recording of an unknown offender with the recording of a suspect in order to find out whether those two voices belong to the same speaker.
This introduction to Forensic Phonetics will allow me to eventually put the emphasis on voice quality as a forensic parameter. It is worth mentioning that the European Network of Forensic Science Institutes (ENFSI) includes voice quality in its recent Best Practice Manual for the Methodology of Forensic Speaker Comparison. In this talk, I will mention the existence of simplified versions of the Vocal Profile Analysis scheme for the perceptual assessment of voice quality and I will highlight the importance of such simplifications, as put forward in a recent international survey on voice quality practices by forensic phoneticians and clinicians. By emphasizing the crossroad where Forensic Phonetics and Clinical Phonetics meet, I hope to create more synergies between two fields of Applied Phonetics where current interdisciplinary collaborations are already proving fruitful for both disciplines.