Forensic Linguistics

Celyn Davies, 3rd year

Introduction

Forensic linguistics is a field of linguistics that deals with the analysis of language in the context of law, either as evidence, which is “the attribution of authorship and the interpretation of meaning”, or as legal discourse (Olsson and Luchjenbroers, 2014, pp.1). Linguist Jan Svartvik is said to be a pioneering Forensic Linguist, after his publication of The Evans Statements: A Case for Forensic Linguistics (1968). In it he analysed a series of statements that were said to have been made to police officers by a man named Timothy Evans, following the death of his wife and child. Svartvik (1968) discovered that the grammatical styles of the statements were different from that of uncontested parts of the statements, making Timothy Evans not guilty (Coulthard et al., 2016).

Language evidence has over the years become an invaluable tool in the criminal justice system, for example in cases of false confessions such as the Birmingham Six. In this case, six men were accused of bombing pubs in Birmingham which led to false confessions being beaten out of them by police (Coulthard et al., 2016). Forensic linguistics aided in proving their innocence. In this essay, I will critically evaluate the importance and role of linguistic evidence in three specific legal cases, focusing on the linguistic tools used to determine authorship and the difficulties associated with this process, in addition to the way that forensic linguists have addressed them.

Linguistic Tools for Attributing Authorship

Firstly, it is important to understand and define the different types of linguistic tools available for forensic linguists, and secondly to describe how they can be used in legal cases. The forensic linguist’s toolkit contains tools such as phonological, morphological, syntactical, lexical, pragmatic and discoursal analysis (Coulthard et al., 2016, pp.121), all of which can help forensic linguists to “measure the ‘rarity’ and therefore the evidential value of individual expressions, or how one can assess the reliability of verbal memory” (Coulthard et al., 2016, pp.6).

Coulthard et al. (2016) describe forensic linguistics as a fastgrowing subfield of linguistics, which has received attention in many legal cases.

Cases

The Unabomber Case

The first case that will be discussed is the case of the Unabomber. Between 1979 and 1995, the Unabomber, later revealed to be a man named Ted Kaczynski, delivered and mailed explosives to academics and corporate executives involved in technology development (Solan and Tiersma, 2005). The explosive devices ultimately killed three people and injured several others. His identity was discovered after he published a 35,000-word manifesto entitled ‘Industrial Society and Its Future’, which Ted Kaczynski’s brother read about and believed it to be written by him. The case was conducted by FBI special agent, James Fitzgerald, who conducted a stylistic comparison of letters sent by the Unabomber to documents known to have been written by Ted Kaczynski (Solan and Tiersma, 2005). The tool of corpus analysis was used by Fitzgerald to discover that both the Unabomber and Kaczynski commonly spelt words unconventionally, such as the use of the British spelling of ‘licence’ instead of the American spelling. Additionally, syntactic analysis was utilised to compare the similar grammatical filler expressions used in both documents, including “take the liberty of” and “at any rate” (Solan and Tiersma, 2005). The use of idioms in both documents were also analysed. Interestingly, Fitzgerald found the Unabomber document and a document written by Kaczynski to include the expression “eat one’s cake and have it” instead of the conventional idiom “have one’s cake and eat it” (Solan and Tiersma, 2005, pp.161). It is important to approach this peculiar phrasing with caution however, as this may just be a part of both the Unabomber and Kaczynski’s idiolects. Idiolects are “similarities in the language use of an individual” (Louwerse, 2004, pp.207). These similarities may be down to factors like changes in location and social setting in the individual’s lifetime (Grant, 2020).

Kaczynski believed the FBI’s stylistic comparison was flawed, so he called upon linguist Robin Lakoff, who submitted an affidavit to the FBI also claiming that the FBI’s comparison was flawed

(Solan and Tiersma, 2005). Lakoff argued that attributing authorship to Kaczynski was problematic for a multitude of reasons. Firstly, although some words that the Unabomber and Kaczynski used were similar, many of them are in fact common words that people use every day. Kaczynski, who worked as an academic, and the Unabomber both also used words that are common among academics (Solan and Tiersma, 2005). This means that anyone who works in academia could use this sort of language. Lakoff concluded that the overlap between the vocabulary and grammar used by the Unabomber and Kaczynski is common to that of the average person, denoting that attributing authorship to Kaczynski would be unfair (Solan and Tiersma, 2005).

In response to Lakoff’s input, the government called upon Donald Foster to provide a declaration. Foster declared that he believed the FBI had done a “remarkably careful job” in attributing authorship to Kaczynski, and that we should not dismiss the unmistakable similarities between the texts (Solan and Tiersma, 2005, pp.162). It is important to consider both sides of this argument to avoid wrongful convictions, but Foster addressed this problem by ensuring the police consider both sides and interpret the linguistic evidence carefully. Furthermore, the police had sufficient nonlinguistic evidence to issue a search warrant and arrest Ted Kaczynski (Solan and Tiersma, 2005).

The Derek Bentley case

The second case discussed in this essay that exhibits the challenges that arise with attributing authorship is the case of Derek Bentley. In the 1950s, two teenaged boys, Derek Bentley, aged 19, and Chris Craig, aged 16, were caught climbing onto the roof of a warehouse, armed with a gun. Three unarmed police officers were called to the scene to arrest them. Bentley instantly surrendered, whereas Craig began shooting. Chris Craig ultimately injured one officer and killed a second (Coulthard et al., 2016). Due to Craig being underage at the time of the murder, he was sentenced to life imprisonment. Bentley, however, was sentenced to death, even though he himself did not murder the officer. Linguistic evidence was the main reason behind Derek Bentley’s prosecution and execution. During Bentley’s statement, he tells the police, “I did not know he was going to use the gun”. The Lord Chief Justice of this case believed this utterance to be of great importance to this case because Bentley said, ‘the gun’ instead of ‘a gun’. The Lord Chief Justice and the jury believed that the way in which he worded this sentence meant that Bentley must have been aware that Chris Craig was in possession of a gun (Coulthard et al., 2016). However, this sentence is contradicted towards the end of Bentley’s statement, as he changes his original sentence to “I did not know Christ had one [gun] until he shot”, thus making Bentley an unreliable witness (Coulthard et al., 2016). One thing we know about Derek Bentley from this case is that he was epileptic, had the mental age of about 11, and could not read nor write (Tuft and Nakken, 2017). With hindsight, attributing authorship to Derek Bentley based solely on this statement quote is problematic, as it may not be a fair representation of what he intended to say and therefore mean.

This was not the only piece of linguistic evidence used to prosecute Bentley. In court, when the police officers were required to give their statements, they declared that Bentley had uttered the words ‘Let him have it, Chris’, just before Chris Craig shot the police officers (Coulthard et al., 2016, pp.174). Single and dual authorship is a factor that can confound authorship attribution, specifically in this case. The three officers at the trial swore on oath that their statements were of unaided monologue dictation, but Bentley believes that the police had taken their questions and his replies to them, and reported them as monologue (Coulthard et al., 2016, pp.175). Malcolm Coulthard, the linguist of this case, agreed with Bentley that the police statements may not have been ‘verbatim record’. This is due to a section of the statement constituting a ‘meta-narrative’ which can be best explained because of “clarificatory questions about Bentley’s knowledge at points in the narrative” (Coulthard et al., 2016, pp.176). Derek Bentley’s guilty verdict was overturned in 1998, unfortunately after his death (Coulthard et al., 2016), giving us more of a reason to criticise the linguistic evidence used to prosecute him.

The Sandra Weddell case

The final case discussed in this essay is the case of Sandra Weddell. In 2007, a police inspector named Garry Weddell sought help from his neighbour to try and find his missing wife, Sandra Weddell. After a short time looking, Sandra was found dead in the garage of her and Garry’s home. She was found with a cable tie around her neck and pronounced dead by asphyxiation (Olsson, 2012). Garry Weddell discovered a printed suicide note next to her body, which was addressed to Garry himself. The police had two candidates for authorship of the note, Sandra Weddell and Garry Weddell. Bedfordshire Police called upon John Olsson, one of the world’s only full-time forensic linguists, to look at the note (Olsson, 2012).

Olsson used pragmatic analysis when analysing the note and discovered many interesting features that helped solve this case. On the alleged suicide note, Sandra Weddell had written her name in full (Sandra Jane Weddell) at the end of the page. Olsson (2012) believed this to be a peculiar feature because it is assumed that Garry would have known who Sandra was just by her first name. Olsson (2012, pp.117) brings up the factor of mode in this instance which refers to the medium of communication, whether this be spoken, written, or dictated (Stockwell, 2007, pp.7, as cited in

Olsson and Luchjenbroers, 2014). He further explains that the type of mode that language is written may differ the way a person uses language. In the case of Sandra’s suicide note, it is typed. Olsson (2012, pp.117) believes that mode was a factor of the authorship of the typed suicide note, as some of it was typed on a laptop, and some was typed on a desktop computer. As these two devices are different in terms of keyboard and mouse, a person may change the way that they write on either device (Olsson, 2012, pp.117). It was important to contemplate this potential factor before jumping to conclusions on the case.

Olsson (2012) also used corpus analysis to break down the note, after he noticed that the average sentence length of the note was just 12 words. When this was compared to previous letters written by Sandra, Olsson (2012) discovered that she wrote much longer sentences, with an instance of her writing over 130 words in one sentence in one of her letters. When this was compared to examples of letters written by Garry, Olsson (2012) discovered that the average sentence length of one of his letters was only 9 words. Olsson (2012, pp.119) concluded that this matter of sentence length can be narrowed down to a factor that can contribute to variations in our writing style called linguistic fingerprint. Olsson (2012, pp.119) describes this as the idea that we all have a unique, identifiable way of using languages. However, the idea of a linguistic fingerprint in the case of Sandra Weddell must be thought of carefully, due to within author variation and inter-author variation. Within author variation refers to how an individual writer’s language use varies, and this includes factors such as personal circumstances and vocabulary (Olsson, 2012, pp.119). This includes how your vocabulary changes when writing an email to a friend (informal) versus writing an email to a work colleague (formal). Olsson (2012, pp.120) describes inter-author variation on the other hand, as how authors may vary from each other, whether this be similar or different social backgrounds or educations levels for example.

The texts written by both Garry and Sandra that were analysed contain variation, in that different types of texts were used. For example, business letters. However, one of Garry’s analysed texts was a personal email. The texts analysed that were written by

Sandra on the other hand, did not include any of her personal communications. Although this factor contributes to variation between the authors, it makes linguistic fingerprint a complicated factor in assessing her style, as suicide notes are considered a form of personal communications (Olsson, 2012, pp.121). Moreover, Olsson (2012, pp.120) scrutinizes the idea of linguistic fingerprint by illustrating the possibility of an author showing a lot of within author variation, but not a lot of inter-author variation across different authors. Seeking to find differences between these authors would be tough (Olsson, 2012). Interestingly, Olsson (2012) questions the use of convergence of style between the couple’s texts. This is when people, a married couple in this case, adopt each other’s language habits. Olsson (2012, pp.121) later debunked this as he has seen no evidence that married couples start to write like each other, especially in this case.

The challenges of linguistic fingerprint and mode were later backed up by additional evidence that the police had discovered, and Garry Weddell was arrested on suspicion of murdering Sandra Weddell. He was however released on bail. Not even a year later,

Garry was found to have murdered his mother-in-law, before committing suicide, thus finally concluding his guilt (Olsson, 2012).

Conclusion

To summarise, forensic linguistics is an important tool in law and the criminal justice system. As evidenced by the cases discussed above, linguistic evidence has been used to determine authorship, prove innocence, and aid in criminal convictions.

Linguistic tools like phonological, morphological, syntactical, lexical, pragmatic, and discoursal analysis can be used to assess the value of an individual’s speech both in cases of unknown authorship, like in the case of the Unabomber, and in cases of known authorship, like in the Derek Bentley case. However, authorship attribution can be a difficult process, and it is critical to approach the analysis with caution. Forensic linguistics is not a key to solving cases, but the evidence above has shown how it can help. The application of forensic linguistics in legal proceedings continues to grow, develop, and gain attention from around the world.

Reference List

Coulthard, M., Johnson, A., & Wright, D. (2016). An introduction to forensic linguistics: Language in evidence. Routledge.

Grant, T. (2020). Text messaging forensics: Txt 4n6: idiolect-free authorship analysis?. In The Routledge handbook of forensic linguistics (pp. 558-575). Routledge.

Leonard, R. A., Ford, J. E., & Christensen, T. K. (2017). Forensic linguistics: Applying the science of linguistics to issues of the law. Hofstra Law Review, 45(3), 11.

Louwerse, M. M. (2004). Semantic variation in idiolect and sociolect: Corpus linguistic evidence from literary texts. Computers and the Humanities, 38, 207-221.

Olsson, J. (2012). Wordcrime : Solving crime through forensic linguistics. Bloomsbury Publishing Plc.