Principles of Forensic Statement Analysis

Linguistic style is defined as the way we speak and write that distinguishes us from other people.

Every one of us has our own unique way of speaking and writing, our own individual dialect called an “idiolect”. Our idiolect reflects every aspect of our life which, in turn, manifests itself in our communications. This allows experts to infer age, gender, education, and the socio-linguistic environment in which a person lives – called linguistic characterisation.

We have favourite words which we use habitually, and which we use in association with other favourite words. We have preferences for certain grammatical constructions, the way we put sentences together, use punctuation, and make spelling mistakes. Collectively, this creates a unique ‘voice’, which linguists use to infer authorship – called Authorship Analysis.

However, this does not mean that linguistic fingerprinting exists. As of yet, no one has come up with the data needed to create a linguistic fingerprint. For this reason, linguistic analysis does not deal with absolutes or percentages. No linguistic analysis for authorship or characterisation can be any % sure or unsure.

The word classes that best characterises linguistic style are Function Words. Including pronouns, conjunctions, prepositions, articles, and adverbs, these are the type of words that we normally pay the least attention to. They are the glue that holds sentences together. Context-free, they remain constant across time, situation, and topics; used subconsciously, they are practically impossible to regulate. As people focus primarily on the information in their story, which requires the manipulation of content words, they tend to ignore Function Words, which appear to serve no purpose other than stringing sentences. Thus, function words form the basis of our linguistic style.

Attribution of Meaning
Everyone speaks and writes in their unique way, creating an idiosyncratic personal dialect which manifests itself in our communication. This “idiolect” incorporates every aspect of our lives, reflecting our gender, age, social background, education, and the socio-linguistic environment in which we live. As a result, every person’s perception of words is different. Thus, it is dangerous to attribute specific meaning to the same word when used by different people across different topics and contexts. Consequently, the psychological profiling of individuals based on their use of language is fraught with danger, and should be left to psychologists.

Deceptive Linguistic Styles
Identifying deception is complicated as there is no one deceptive linguistic style that people default to all the time. However, certain language dimensions are known to characterise deception:

Dependence is a person’s involvement with or distancing from the information being provided. One way a person can distance himself from the information he is providing is by manipulation of the 1st person pronouns ‘I’, ‘me’ and ‘my’. Their absence or presence in a statement allows the author to control the amount of involvement he has with the people, objects, and places being referred to.

In this example, the author stops using “I” in favour of “me”, therefore turning from the agent of the action (proactive) into the recipient of the action (receptive). The increased use of “my” gives the impression that the author is still there in the story, but the focus is on “my pistol” and “my elbow” instead of him as a person.

Uncertainty is the suggestion of something happening without being clear about what actually happened. This could be through the use of negation (e.g. no, not, never) to say what didn’t happen, in combination with the use of Retractors (e.g. but, however, yet), words which partially or completely withdraw a previous assertion.

Vagueness refers to the blurring as to what actually happened, through the use of verb strings and vague pronoun references.

In this example, the use of verb strings (more than one verb being used as a single verb e.g. tried to hit, trying to hold) suggest an action which did not actually happen. At the same time, the use of “guy” is applied to two different individuals, but only vaguely identifies which one is doing what at the time.

These language dimensions combine to create a number of distinct deceptive linguistic styles which deceivers pick and choose from to achieve best results depending on the circumstances in which they find themselves.