Forensic speechreading explained

Forensic speechreading (or forensic lipreading) is the use of speechreading for information or evidential purposes. Forensic speechreading can be considered a branch of forensic linguistics. In contrast to speaker recognition, which is often the focus of voice analysis from an audio record, forensic speechreading usually aims to establish the content of speech, since the identity of the speaker is usually apparent. Often, it involves the production of a transcript of lip-read video-recordings of talk that lack a usable audiotrack, for example CCTV material. Occasionally, 'live' lipreading is involved, for example in the Casey Anthony case.[1] Forensic speechreaders are usually deaf or from deaf families (CODA), and use speechreading in their daily lives to a greater extent than people with normal hearing outside the deaf community. Some speechreading tests suggest deaf people can be better lipreaders than most hearing people.[2]

Speechreading expertise

No tests of speechreading have yet been developed in a forensic context, that is, to benchmark individual skills in speechreading from a video record, including the production of a reliable transcript.[3] For many years, UK agencies made extensive use of one particular speechreader, whose reports are now not to be used for evidential purposes.[4] Several speechreaders and deaf professionals currently offer these services. Expert speechreaders may be able to advise on various issues, including whether a video record is or is not speechreadable, and the accent and language used by a talker.[5] Commissioning agents need to be aware of issues inherent in the unreliability of speechreading, and be prepared to treat such advice with caution.[6]

The law

In the UK, a landmark case and appeal (R. v Luttrell et al., 2004) established the admissibility of lipreading evidence.[7] However, the appeal court also required that the judge should issue a special warning as to its risks and limitations.[8]

While lipread speech can carry useful speech information, it is inherently less accurate than (clearly) heard speech because many distinctive features of speech are produced by actions of the tongue within the oral cavity and are not visible.[9] [10] This is a limitation imposed by speech itself, not the expertise of the speechreader. It is the main reason why the accuracy of a speechreader working on a purely visual record cannot be considered wholly reliable, however skilled they may be and irrespective of hearing status.[10] The type of evidence and the utility of such evidence varies from case to case.

In the US, there is debate concerning the admissibility of speechreading evidence and its status,[11] especially in relation to variations in state and federal evidential procedures, and with respect to the privacy implications of the Fourth Amendment to the US constitution.[12]

Three UK cases involving speechreading evidence

Notes and References

  1. News: Did Casey Anthony Contradict Her Own Defense by Mouthing Words . ABC News . July 5, 2011 . October 5, 2012.
  2. 10.1044/1092-4388(2007/080) . Enhanced Visual Speech Perception in Individuals with Early-Onset Hearing Impairment . 2007 . Auer . Edward T. . Bernstein . Lynne E. . Journal of Speech, Language, and Hearing Research . 50 . 5 . 17905902 . 1157–65.
  3. Web site: Ruth . Campbell . Tara-Jane Ellis . Mohammed . 2010 . Speechreading for information gathering: a survey of scientific sources . Deafness Cognition and Language Research Centre .
  4. News: CPS drops So Solid expert witness . BBC News . 2005-06-27 . 2012-10-15.
  5. Web site: FAQ . Lip Reading Translation . 2012-10-15.
  6. Web site: Ruth . Campbell . Guidance for organizations planning to use lipreading for information gathering . Deafness Cognition and Language Research Centre . 2010 . November 4, 2012.
  7. original case notes; http://lexisweb.co.uk/cases/2004/may/r-v-luttrell-and-others-r-v-dawson-and-another: appeal court decision; http://www.bailii.org/cgi-bin/markup.cgi?doc=/ew/cases/EWCA/Crim/2004/1344.html&query=luttrell&method=boolean
  8. updated ruling in relation to expert witness evidence; Mary Luckham 'Forensic lipreading',http://www.qebholliswhiteman.co.uk/articles-pdfs/forensic-lip-reading.pdf
  9. 3950202 . 1986 . Breeuwer . M . Plomp . R . Speechreading supplemented with auditorily presented speech parameters . 79 . 2 . 481–99 . The Journal of the Acoustical Society of America . 10.1121/1.393536. 1986ASAJ...79..481B . 43878778 .
  10. 20211120 . 2010 . Auer . Edward T. . Investigating Speechreading and Deafness . 21 . 3 . 163–8 . 10.3766/jaaa.21.3.4 . Journal of the American Academy of Audiology. 3715375 .
  11. Web site: e-wire article: Taking experts out of the court . Jspubs.com . 2004-07-15 . 2012-10-15.
  12. Web site: June 4, 2011 . CM . Read My Lips, No Lip Reading Testimony?: Court Of Appeals Of Indiana Opinion Poses Question About Lip Read Statements . EvidenceProf Blog . 2012-10-15.
  13. Web site: Nine jailed over £11m stolen goods . BBC News . 2003-02-27 . 2012-10-15.
  14. Web site: Luttrell & Ors, R v [2004] EWCA Crim 1344 (28 May 2004) |publisher=Bailii.org |date= |access-date=2012-10-15].
  15. Web site: Lip reader saw Fraser's incriminating conversations. 2 February 2003. 27 January 2018. www.telegraph.co.uk.
  16. Web site: Press Office - Frontline Scotland reveals new evidence in Arlene Fraser murder case . BBC . 2005-10-19 . 2012-10-15.
  17. Web site: John Terry's racist slur uncensored in slow motion . YouTube . 2011-12-02 . 2012-10-15.
  18. Web site: Racist and Religious Crime: Legal Guidance: The Crown Prosecution Service . Cps.gov.uk . 2012-10-15.
  19. The Guardian 12 July 2012
  20. Web site: R -v- John Terry judgement. 13 July 2012. www.judiciary.gov.uk.
  21. Web site: Terry not guilty of racist abuse. 13 July 2012. BBC.
  22. The Football Association and John Terry
  23. The Football Association and John Terry (1.5)
  24. Web site: John Terry defence 'improbable, implausible and contrived'. 5 October 2012. BBC.
  25. Web site: John Terry judgment: Main findings of the FA's regulatory commission. 5 October 2012. the Guardian.