skip to content

Phonetics Laboratory

 
Speaker characteristics, forensic phonetics, phonetic realisation of varieties of English

Biography

After completing a Ph.D. entitled The Role of Formant Dynamics in Determining Speaker Identity under the supervision of Francis Nolan, I worked as a Research Associate on the ESRC projects DyViS and VoiceSim, in the Phonetics Laboratory at the University of Cambridge, then took up a British Academy Postdoctoral Fellowship, also in the Phonetics Laboratory in Cambridge. This was followed by various part-time posts as Lecturer at the University of Hertfordshire and as College Lecturer and Admissions Tutor at Clare College, then Selwyn College, Cambridge, and as a Senior Research Associate in the Phonetics Laboratory, University of Cambridge, before commencing as University Lecturer in Phonetics. I am currently Principal Investigator on the ESRC-funded IVIP project ‘Improving Voice Identification Procedures’.

Education

Ph.D. (Linguistics), University of Cambridge
M.Phil. (Linguistics), University of Cambridge
B.A. (Linguistics), University of Melbourne
B.Sc. (Mathematics and Statistics), University of Melbourne

Research

My research interests in phonetics broadly fall into two main areas, speaker characteristics and the phonetics of varieties of English. I use experimental methods and approaches involving spontaneous speech, and am concerned with improving our understanding of the roles of individual, social and historical factors in theories of speech production and perception.

My research to date has primarily focussed on speaker characteristics and forensic phonetics. My Ph.D., entitled ‘The Role of Formant Dynamics in Determining Speaker Identity’, investigated ways of using formant frequency dynamics to characterise a speaker and developed techniques using polynomial equations. In the DyViS project, ‘Dynamic Variability in Speech: A Forensic Phonetic Study of British English’ (UK ESRC RES-000-23-1248), with Francis Nolan, Gea de Jong and Toby Hudson, we created the first large-scale forensically oriented speech database for English (100 male speakers of SSBE in several speaking styles), whose methodology has since inspired the development of a number of new forensic phonetic databases. As well as enabling me to expand my research on formant dynamics, the DyViS database facilitated our studies of fundamental frequency distribution in SSBE and sound change as a source of speaker-distinguishing information, and has since been used extensively by many other forensic phonetic researchers.

Also with a forensic focus, I have an ongoing programme of research investigating the potential of disfluency features to distinguish speakers. In collaboration with Martin Duckworth, I have developed and implemented TOFFA (Taxonomy of Fluency Features for Forensic Analysis), a methodology for the analysis of fluency behaviour in forensic casework. We are extending this work across different speaking styles, larger populations, more varieties of English, and other languages.

Another area of my interest within forensic phonetics is the use of earwitnesses to identify a voice in legal cases where no recording of the voice is available. I am consulted by the police as an expert witness regarding the construction of ‘voice parades’ for such cases, and have been researching the use of the statistical technique multi-dimensional scaling to improve the fairness of the procedure for selecting the foil voices for a voice parade. My research projects in earwitness evidence include the VoiceSim project, ‘Voice Similarity and the Effect of the Telephone: A Study of the Implications for Earwitness Evidence’ (UK ESRC RES-000-22-2582), my British Academy Postdoctoral Fellowship project, 'A Phonetic Theory of Voice Similarity', and most recently the IVIP project ‘Improving Voice Identification Procedures’ (UK ESRC ES/S015965/1), for which I am Principal Investigator. IVIP is an interdisciplinary project bringing together colleagues in linguistics, psychology, criminology and law. The project is investigating whether higher accuracy in earwitness identification can be achieved by improving voice parade methodology, and exploring ways to improve the interaction of the criminal justice system with the use of earwitness evidence.

Beyond yet still related to forensic phonetics, I have an ongoing interest in the phonetic realisation of varieties of English, motivated by questions relating to speaker characteristics, language variation and change, and sociophonetics. As a native speaker of Australian English, I am particularly interested in this variety and have published and presented a number of acoustic and sociophonetic studies of variation in the production of its consonants. I am currently engaged in research into plosive realisation in mainstream and Aboriginal varieties of Australian English with Debbie Loakes.

Publications

Key publications: 
  • L. Gerlach, K. McDougall, F. Kelly, A. Alexander and F. Nolan (2020) ‘Exploring the Relationship Between Voice Similarity Estimates by Listeners and by an Automatic Speaker Recognition System Incorporating Phonetic Features.’ Speech Communication 85-95. [pre-print]
  • K. McDougall and M. Duckworth (2018) ‘Individual Patterns of Disfluency Across Speaking Styles: A Forensic Phonetic Investigation of Standard Southern British English.’ International Journal of Speech, Language and the Law 25.2: 205-230.
  • K. McDougall and M. Duckworth (2017) ‘Profiling Fluency: An Analysis of Individual Variation in Disfluencies in Adult Males.’ Speech Communication 95: 16-27.
  • K. McDougall, F. Nolan and T. Hudson (2015) ‘Telephone Transmission and Earwitnesses: Performance on Voice Parades Controlled for Voice Similarity.’ Phonetica 72: 257-272. DOI: 10.1159/000439385 [pre-print]
  • K. McDougall (2013) ‘Assessing Perceived Voice Similarity Using Multidimensional Scaling for the Construction of Voice Parades.’ International Journal of Speech, Language and the Law 20.2: 163-172.
  • K. McDougall (2006) ‘Dynamic Features of Speech and the Characterisation of Speakers: Towards a New Approach Using Formant Frequencies.’ International Journal of Speech, Language and the Law 13.1: 89-126.
  • K. McDougall (2004) ‘Speaker-Specific Formant Dynamics: An Experiment on Australian English /aI/.’ International Journal of Speech, Language and the Law 11.1: 103-130.

 

Other publications: 

 

Formant frequencies and speaker characterisation (including formant dynamics)

  • See also McDougall (2004) and McDougall (2006) in ‘Key Publications’ above.
  • M. Duckworth, K. McDougall, G. de Jong and L. Shockey (2011) ‘The Consistency of Formant Measurements in High Quality Audio Data: the Effect of Agreeing Measurement Procedures.’ International Journal of Speech, Language and the Law 18.1: 35-51.
  • G. de Jong, K. McDougall, T. Hudson and F. Nolan (2007) ‘The Speaker-Discriminating Power of Sounds Undergoing Historical Change: A Formant-Based Study’, In J. Trouvain and W. Barry (eds.), Proceedings of the 16th International Congress of Phonetic Sciences, 6-10 August 2007, Saarbrücken, 1813-1816. [pdf]
  • G. de Jong, K. McDougall and F. Nolan (2007) ‘Sound Change and Speaker Identity: An Acoustic Study.’ In C. Müller (ed.), Speaker Classification. Berlin: Springer. Vol. 2: 130-141.
  • K. McDougall and F. Nolan (2007) ‘Discrimination of Speakers Using the Formant Dynamics of /u:/ in British English’, In J. Trouvain and W. Barry (eds.), Proceedings of the 16th International Congress of Phonetic Sciences, 6-10 August 2007, Saarbrücken, 1825-1828. [pdf]
  • K. McDougall (2006) ‘The Role of Formant Dynamics in Determining Speaker Identity.’ Ph.D. abstract. International Journal of Speech, Language and the Law. 13.1: 144-145.
  • F. Nolan, K. McDougall, G. de Jong and T. Hudson (2006) ‘A Forensic Phonetic Study of 'Dynamic' Sources of Variability in Speech: The DyViS Project.’ In P. Warren and C.I. Watson (eds.), Proceedings of the 11th Australasian International Conference on Speech Science and Technology, 6-8 December 2006, Auckland: Australasian Speech Science and Technology Association, 13-18. [pdf] 
  • K. McDougall (2005) The Role of Formant Dynamics in Determining Speaker Identity. Ph.D. Dissertation, Department of Linguistics, University of Cambridge.
  • K. McDougall (2003) ‘Individual Differences in the Formant Dynamics of Vowels at Different Levels of Stress.’ In M. J. Solé, D. Recasens and J. Romero (eds.), Proceedings of the 15th International Congress of Phonetic Sciences, 3-9 August 2003, Barcelona: Causal, 1611-1614. [pdf]
  • K. McDougall (2002) ‘Speaker-Characterising Properties of Formant Dynamics: A Case Study.’ In C. Bow (ed.), Proceedings of the 9th Australian International Conference on Speech Science and Technology, 3-5 December 2002, Melbourne: Australian Speech Science and Technology Association, 403-408.

Disfluency features and speaker characterisation

  • See also McDougall and Duckworth (2017) and McDougall (2018) in ‘Key Publications’ above.
  • K. McDougall, R. Rhodes, M. Duckworth, J.P. French, C. Kirchhübel (2019) ‘Application of the ‘TOFFA’ Framework to the Analysis of Disfluencies in Forensic Phonetic Casework.’ In Sasha Calhoun, Paola Escudero, Marija Tabain and Paul Warren (eds.) Proceedings of the 18th International Congress of Phonetic Sciences, 5-9 August 2019, Melbourne. Australasian Speech Science and Technology Association Inc., 731-735.
  • K. McDougall, M. Duckworth and T. Hudson (2015) ‘Individual and Group Variation in Disfluency Features: A Cross-Accent Investigation.’ In: The Scottish Consortium for ICPhS 2015 (ed.) Proceedings of the 18th International Congress of Phonetic Sciences, 10-14 August 2015, Glasgow, Paper number 0308, 1-5. [pdf]

Earwitness evidence (especially perceived voice similarity)

  • See also Gerlach et al. (2020), McDougall et al. (2015) and McDougall (2013) in ‘Key Publications’ above.
  • G. de Jong-Lendle, F. Nolan, K. McDougall and T. Hudson (2015) ‘Voice Lineups: A Practical Guide.’ Proceedings of the 18th International Congress of Phonetic Sciences, 10-14 August 2015, Glasgow. Paper number 0598. 1-5. [pdf]
  • K. McDougall (2013) ‘Earwitness Evidence and the Question of Voice Similarity.’ British Academy Review 21: 18-21. [pdf]
  • F. Nolan, K. McDougall and T. Hudson (2013) 'Effects of the Telephone on Perceived Voice Similarity: Implications for Voice Line-ups.' International Journal of Speech, Language and the Law 20.2: 229-246.
  • F. Nolan, K. McDougall and T. Hudson (2011) ‘Some Acoustic Correlates of Perceived (Dis)similarity between Same-Accent Voices.’ In W.-S. Lee and E. Zee (eds.), Proceedings of the 17th International Congress of Phonetic Sciences, 17-21 August 2011, Hong Kong, 1506-1509. [pdf]

Other forensic phonetic topics

  • J.P. French, F. Nolan, P. Foulkes, P. Harrison and K. McDougall (2010) ‘A Position Statement Concerning Use of Impressionistic Likelihood Terms in Forensic Speaker Comparison Cases: Rejoinder to the Response of Rose and Morrison’ International Journal of Speech, Language and the Law 17.1: 143–152.
  • T. Hudson, K. McDougall and V. Hughes (in press) ‘Forensic Phonetics.’ In J. Setter and R. Knight (eds.) Cambridge Handbook of Phonetics. Cambridge University Press.
  • S. Lawrence, F. Nolan and K. McDougall (2008) ‘Acoustic and Perceptual Effects of Telephone Transmission on Vowel Quality.’ International Journal of Speech, Language and the Law 15.2: 161-192.
  • F. Nolan, K. McDougall, G. de Jong and T. Hudson (2009) ‘The DyViS Database: Style-Controlled Recordings of 100 Homogeneous Speakers for Forensic Phonetic Research.’ International Journal of Speech, Language and the Law 16.1: 31–57.
  • T. Hudson, G. de Jong, K. McDougall, P. Harrison and F. Nolan (2007) ‘F0 Statistics for 100 Young Male Speakers of Standard Southern British English’, In J. Trouvain and W. Barry (eds.), Proceedings of the 16th International Congress of Phonetic Sciences, 6-10 August 2007, Saarbrücken, 1809-1812. [pdf]

Phonetic variation in varieties of Australian English

  • D. Loakes, K. McDougall, J. Clothier, J. Hajek and J. Fletcher (2018) ‘Sociophonetic Variability of /t/ in Aboriginal and Mainstream Australian English.’ In J. Epps, J. Wolfe, J. Smith and C. Jones (eds.), Proceedings of the 17th Australasian International Conference on Speech Science and Technology, 4-7 December 2018, Australasian Speech Science and Technology Association, Sydney, 5-8. [pdf]
  • K. McDougall and M.J. Jones (2011) ‘Liquid Polarisation in Australian English.’ In W.-S. Lee and E. Zee (eds.), Proceedings of the 17th International Congress of Phonetic Sciences, 17-21 August 2011, Hong Kong, 1358-1361. [pdf]
  • D. Loakes and K. McDougall (2010) ‘Individual Variation in the Frication of Voiceless Plosives in Australian English: a Study of Twins’ Speech.’ Australian Journal of Linguistics 30.2: 155-181.
  • M.J. Jones and K. McDougall (2009) ‘The Acoustic Character of Fricated /t/ in Australian English: A Comparison with /s/ and /esh/.’ Journal of the International Phonetic Association 39.3: 265-289. [pdf, © International Phonetic Association]
  • D. Loakes and K. McDougall (2007) ‘Frication of Australian English /p t k/: Group Tendencies and Individual Differences’, In J. Trouvain and W. Barry (eds.), Proceedings of the 16th International Congress of Phonetic Sciences, 6-10 August 2007, Saarbrücken, 1445-1448. [pdf]
  • M.J. Jones and K. McDougall (2006) ‘A Comparative Acoustic Study of Australian English Fricated /t/: Assessing the Irish (English) Link.’ In P. Warren and C.I. Watson (eds.), Proceedings of the 11th Australasian International Conference on Speech Science and Technology, 6-8 December 2006, Auckland: Australasian Speech Science and Technology Association, 6-12. [pdf]
  • D. Loakes and K. McDougall (2004) ‘Frication of /k/ and /p/ in Australian English: Inter- and Intra-Speaker Variation.’ In S. Cassidy, F. Cox, R. Mannell and S. Palethorpe (eds.), Proceedings of the 10th Australian International Conference on Speech Science and Technology, 8-10 December 2004, Sydney: Australian Speech Science and Technology Association, 171-176. [pdf]

Other topics

  • K. McDougall (2003) ‘Vowel-to-Vowel Coarticulatory Evidence of the “Targetful” Nature of Schwa.’ In S. Palethorpe and M. Tabain (eds.), Proceedings of the 6th International Seminar on Speech Production, 7-10 December 2003, Sydney: Macquarie University, 161-166.
  • K. Kawasaki and K. McDougall (2003) ‘Implications of Representations of Casual Conversation for Second Language Learners: A Case Study in Japanese Sentence Final Particles.’ Japanese Language Education Around the Globe 13: 41-55.

Teaching and Supervisions

Teaching: 

I contribute to teaching and supervision in these courses in the Linguistics Tripos:

  • Paper 1 - Sounds and Words

  • Paper 6 - Phonetics

I also contribute to the M.Phil. Lent Term course Experimental Phonetics and Phonology.

 

Research supervision: 

I welcome enquiries from potential M.Phil. and Ph.D. students.

 

PhD Supervisees

Name Thesis title
   
Linda Gerlach Assessing perceived voice similarity using phonetic techniques and automatic approaches

 

Other Professional Activities

I undertake forensic phonetic expert witness work in collaboration with Prof. Francis Nolan. This includes tasks such as speaker identification/comparison, voice parades (earwitness identification), transcription and questioned utterance analysis.

 

Professional Memberships

  • Australian Linguistic Society
  • Australasian Speech Science and Technology Association
  • British Association of Academic Phoneticians
  • International Association for Forensic Phonetics and Acoustics
  • International Phonetic Association
University Lecturer in Phonetics
Fellow of Selwyn College

Affiliations

Collaborator profiles: 
Classifications: