Welcome to ILE

The Institute for Linguistic Evidence was founded in 1998, the first non-profit scientific research organization devoted to developing and testing methods in forensic linguistics. The Institute was founded, at the urging of my program manager Dr. Dick Rau, when I completed my Visiting Research Fellowship (1995-98) at the US Department of Justice, National Institute of Justice. Dick believed that research was fundamental to improving forensic sciences in general, and forensic linguistics in particular. ILE supports the vision that forensic linguistics must be built on real research.ile logo

As Executive Director of the Institute, I am delighted that you are interested in our research and professional service to the linguistics, security, legal and intelligence communities. With a small group of scientists, legal analysts and programmers committed to the highest standards for forensic science and civil liberties, ILE performs basic research so that attorneys and investigators can have reliable tools for using linguistic evidence with fairness and confidence. ILE's sister organization, ALIAS Technology LLC , provides software and services to the legal and security communities.


  • To research and develop proven and reliable methods for answering forensically significant questions about language
  • To develop methods based in linguistic theory, standard analytical techniques in linguistics, and computational linguistics
  • To educate the public and legal systems about the proper use of language as evidence and the danger of using methods not grounded in linguistics


A text with some value in legal proceedings comes in many different forms to police officers, detectives, private investigators, security specialists, intelligence analysts, attorneys and private individuals. Some civil disputes are obviously associated with certain types of linguistic evidence, such as trademarks, service marks, and patent applications. In certain criminal scenarios, some forms of linguistic evidence are likewise obvious: a bank robbery note, a threat letter, a suicide note, a ransom note.


It is clear, from these kinds of documents, that linguistic evidence can play a crucial role in investigating a crime, and the crime with which such a document is associated is also obvious, (although sometimes this kind of document is a red herring to cover up a different kind of crime). For instance, in actual cases, a suicide note has been written to disturb or cover up a murder; a threat letter has been sent in order to mislead investigators away from conspirators.  Whether in civil or criminal scenarios, the words themselves are critical pieces of evidence in proving some aspect of the crime or civil trespass.

Other kinds of linguistic evidence are not so well-known, and the crimes or civil actions to which they attach are likewise not so obvious. Blog posts, dating website profiles, handwritten codicils and wills, business emails and memoranda, personal emails within a family or corporation, graffiti sprayed on a shop’s wall –these kinds of linguistic evidence can occur in many different crimes or civil and security investigations.


At ILE our research agenda is set for the "four corners of forensic linguistics," to reflect the fundamental questions we have been asked, repeatedly, about some document relevant to a case. Often the crucial investigative issues are:

1. author/speaker identification: Who authored this document? Who spoke this voicemail message?

2. text similarity: Are these texts or screen names related to each other? Are these trademarks too similar? Are these manuals too close for comfort?

3. text typing: Is this document really what it purports to be --- is it a real suicide note, a real threat letter, a real confession, a real predatory chat, etc?

4. linguistic profiling: What can be determined about the author’s background from this text?


The stakeholders for linguistic evidence are

  • law enforcement,
  • private and civil investigators, 
  • the national, business and executive security communities,
  • the academic and research community,
  • the legal community, and
  • any citizen whose life, liberty and finances are being affected by the proper or improper use of linguistic evidence in criminal or civil litigation.

From its inception, ILE has recognized our stakeholders' need for reliable methods of answering the fundamental questions. ILE has a history of testing methods to find out how well they work.


For over twenty years, we have been testing language-based methods to find out if these methods can be trusted. During these twenty years, we have found that some readily-accepted, popular ideas just don't work when they are actually tested, and we have found some that do work well. We report these findings so that our stakeholders will be wary of methods that aren't reliable and consider using methods that do work well.

We run our tests outside of any litigation on "ground truth data," (data that we know the correct answers for, like who really did write which document). Trying to figure out if a method works in the middle of a case is far too late; we work proactively to develop tools from methods that we know work, before a case arises. And testing a method on data that is not "ground truth" (even if the dataset is easy to get or convenient) is futile as no real error rates can be calculated and the researchers never really know how well a method worked to get the correct answers.

When our research --testing, tweaking, re-testing-- gets a method to an acceptable level of reliable performance, we transfer the technology over to our sister organization, ALIAS Technology LLC (which you can find out about under Tools).

And during these twenty years, we have met with resistance and other obstacles. We continue our validation testing and empirical research, even if it is not popular in some quarters, because our system of justice often relies on forensic evidence. The strongest system of justice and security cannot be built on shoddy investigation or junk science: only the strongest science can meet the needs of a democratic system of justice and security. Here in the United States, we are so blessed with a justice system which relies on both prosecutorial discretion and a strong defense. Prosecutors I have worked with want to make their case based on strong forensic evidence: they don't want to put forward junk science. Defense attorneys I have worked with also want to use the strongest forensic science for their clients. Yes, of course, there are experts in the system more interested in money than justice, fame than fairness; every profession has that kind of problem. But at ILE we believe that fundamentally most of us involved in the justice system are all looking for the same thing: good investigation that finds evidence, and strong forensic science to analyze the evidence.

My colleagues and I are working to make sure that forensic linguistics matures into a strong forensic science, able to serve the security, legal and intelligence communities with robust tools for reliable results.


Through ILE, you will find an interdisciplinary professional society TALE: The Association for Linguistic Evidence . As a professional association, TALE provides a Code of Ethics to which members adhere, an Annual Winter Conference in conjunction with the Linguistic Society of America, and a peer-reviewed journal.  TALE's Honorary Fellows include linguists, criminologists, intelligence and security analysts whose work exemplifies the ILE paradigm. TALE honors these members of our community because we value their work, and believe that they provide examples for us to follow in their footsteps -- to uphold scientific standards, to develop reliable and replicable methods, and to meet the needs of the legal and investigative communities in ways that are grounded in the established sciences of linguistics, psychology and computer science.

The open access journal LESLI: Linguistic Evidence in Security, Law and Intelligence is published twice a year for the stakeholders of forensic linguistics and provides rigorous research article, stimulating policy discussions and resource essays. For weekly discussion, join our LinkedIN group Forensic Linguistic Evidence or our Telling TALE: Forensic Linguistics Blog.

Thank you for visiting this site and reading about forensic linguistics -the science of language in support of justice.

---Carole E Chaski PhD