WHAT IS LINGUISTIC EVIDENCE?
A text with some evidentiary 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 actions 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 obfuscate a murder; a threat letter has been sent in order to provide a false lead 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.
But some forms 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 kinds of crimes or civil and security investigations.
Often the crucial investigative issues are:
1. author/speaker identification: Who authored this document? Who spoke this voicemail message?
2. intertextuality: Are these texts or screen names related to each other? Are these trademarks too similar?
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 the law enforcement, investigative and security community, the academic and research community, the legal community, and any citizen whose life, liberty or finances can be affected by the proper or improper use of linguistic evidence in criminal or civil litigation.