The Language Detectives: Solving Puzzles With Forensic Linguistics

From the courtroom to the Twitterverse, a look at how forensic linguists use language patterns to solve the world’s mysteries.
forensic linguistics

What do Jack the Ripper’s letters, the Unabomber’s manifesto and President Trump’s tweets have in common? They’ve all been extensively analyzed using forensic linguistics — the application of linguistic knowledge in legal and criminal contexts. In other words, professionals you could conceivably consider “language detectives” have scrutinized these works, looking for clues that might indicate authorship or link them to other writings.

The field of forensic linguistics has recently come back into the spotlight, thanks in part to an anonymous New York Times op-ed by a senior administration official that criticized Trump from an “insider’s perspective.” Of course, it led everyone with a social media account to wildly speculate on who the author could be. Not everyone is equipped to do so, however. That’s where the forensic linguists come in.

Experts like Robert Leonard and Shlomo Argamon have been quoted recently warning against unscientific speculations and say it would take more time and more documents to even attempt to identify the op-ed writer. They argue that fixating on specific words like “lodestar” — which Twitter users were quick to point out is a word Vice President Mike Pence uses regularly — is pointless because the author could have used it intentionally to throw people off their trail.

But forensic linguistics isn’t a brand new discipline, and this certainly isn’t the first time the field has made headlines. Before we get into how it’s been used to crack important cases, let’s examine how the process of language sleuthing actually works.

A Way With Words

Forensic linguistics is broadly defined as the study and application of language in a forensic context. But what does this mean in practice?

Leanne Bartley, a lecturer in applied linguistics at Swansea University who has done quite a bit of research in the forensic linguistics field, explains: “Forensic linguistics encompasses a fairly wide range of topics, including legal jargon, authorship attribution, courtroom interpreting, lay participants in the judicial process, false confessions — to name but a few.”

Bartley has focused her studies primarily on sexual assault cases. She examines how language is used by survivors to describe what happened to them and, conversely, how it can be used to bring about wrongful convictions.

“This latter area is something I intend to continue to explore in order to work toward minimizing the occurrence of miscarriages of justice in the future,” Bartley says.

When describing her process in such cases, Bartley says she starts by trying to pinpoint the focus of the discourse. For instance, did the prosecuting attorney say, “the defendant sexually assaulted this girl” or “this girl was sexually assaulted”?

In the latter statement, Bartley says, “There is no explicit mention of the alleged attacker, thus shifting the focus away from the party responsible and, in turn, potentially affecting the way in which the listener (i.e. juror) construes what happened.”

But that’s just one example of how forensic linguistics can play a role in important court cases. Krzysztof Kredens, co-director of the Centre for Forensic Linguistics, told us about a case he worked on in 2012, in which he was asked to determine whether a non-native English speaker with limited proficiency in the language could have produced a specific complex business document.

Kredens says he “examined the purported author’s emails to establish a linguistic profile, and then analyzed the lexical and syntactic structures of the disputed document.” After comparing the two, he concluded that it was unlikely the non-native English speaker wrote the document.

Murder, They Wrote: The Unabomber And Jack The Ripper

Highly publicized murder trials have been some of the most well-known cases involving forensic linguistics. In fact, the case of the Unabomber is credited with the rise of forensic linguistics. Starting in 1978, the person who became known as “the Unabomber” sent homemade bombs to random people over a 17-year period, which resulted in 23 injured victims and three deaths. For a while, there were few leads on who the perpetrator could be.

It was forensic linguist James Fitzgerald who convinced the FBI to make the Unabomber’s 35,000-word “manifesto” public in 1995. With the help of tips from the public and a careful analysis of the Unabomber’s writing style, Fitzgerald was able to link the essay to Ted Kaczynski. Fitzgerald’s work brought about a search warrant for Kaczynski’s cabin, where they found enough evidence to convict him.

You can find another case of forensic linguistics that provides insight into England’s most notorious murderer: Jack the Ripper. Because the Jack the Ripper’s serial killings took place much earlier (London, 1888) than the Unabomber’s attacks, the forensic linguistic component happened recently.

In early 2018, Andrea Nini, a forensic linguist at the University of Manchester, looked into letters allegedly signed by Jack the Ripper that were sent to the press, the police and other groups in the aftermath of the murders. Many of the letters were considered copycat hoaxes, but after studying two of the earlier letters, known as the “Dear Boss” letter and the “Saucy Jacky” postcard, Nini concluded that there is “very strong linguistic evidence that these two texts were written by the same person.”

And no, Jack the Ripper didn’t use the word “lodestar” in all of his writing; usually, the findings sound pretty mundane. One example of a linguistic similarity Dr. Nini found between the two letters was the use of the phrasal verb “to keep back,” meaning “to withhold.” He also found distinct similarities in the lexicogrammatical structures (the relationship between grammar and vocab).

Despite these recent developments that highlight an important use case for forensic linguistics, the Jack the Ripper case remains unsolved to this day.

Modern-Day Changes, Challenges And Rewards

Technological advances are reshaping the field of forensic linguistics in ways that are both helpful and more difficult.

Kredens explains: “With the spread of social media, a lot of crime has moved online and there is definitely an increase in demand for forensic linguistic analysis.” But at the same time, he says, there are more and more tools at their disposal. “I think the future will also bring advances in computational analysis that will help us make sense of what’s going on in cases involving a lot of data.”

And while working as a forensic linguist certainly comes with its fair share of challenges, including having to explain their findings to laypeople and withstand often heated cross-examination from attorneys, it’s a very rewarding line of work. Whether helping get justice for victims, clearing the names of those wrongfully convicted or even just identifying the author of a controversial article, there is a tangible and satisfying sense that you’re doing something worthwhile.

“I always think that the most rewarding part of any job or any situation is when you see that, no matter how small, you made a difference,” Bartley says. “I feel that forensic linguistics can do that.”

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Dylan Lyons

Dylan is a senior content producer, overseeing video and podcast projects for the U.S. team. He studied journalism at Ithaca College and has an MBA from NYU. Before joining Babbel, Dylan managed social media for CBS News. His interests include reading, writing, politics, and anything sweet. Dylan lives in New York City.

Dylan is a senior content producer, overseeing video and podcast projects for the U.S. team. He studied journalism at Ithaca College and has an MBA from NYU. Before joining Babbel, Dylan managed social media for CBS News. His interests include reading, writing, politics, and anything sweet. Dylan lives in New York City.