Emerson once said, "Words are also actions, and actions are a kind of words." The two are interchangeable in the world of fraud. You speak and write for a purpose and that purpose is then hinted to the listener or reader through your word choice. That becomes a part of a linguistic pattern that alerts the observer or investigator. Every word that the individual uses in a narrative are a personal choice and indicate the behavior of the person.
Investigative discourse analysis is the systematic and close investigation of written and spoken speech. Movies have malformed our perception of crime, and led us to assume that everything related to the investigation of fraud and crimes are filled with action, adventure, and hints at every corner, and that the entire department is willing to put aside all other cases just to solve that one particular one; of course, in the end, the main character solves the case and everyone's happy except the bad guy. In truth, the examination of cases involving fraud and deception are puzzle pieces that require patience, long hours behind a desk, and a few triple espressos--that's as adventurous as it gets.
Fraud examiners see fraud cases as the equivalent of a sudoku or a crossword puzzle in the Sunday paper, and if it were not for our passion to unveil the deceit, fraud cases are better off gathering dust and cobwebs from the shelves. One of the things that they carefully look into are linguistics. For example, someone who is trying to sound convincing or deceiving, uses a more slippery word choice, choosing either soft and pitiful wording. When a speaker uses expressions such as “Let’s see” or “that’s it”, they're trying to convince the listener or reader to pay attention to what follows.
Everything comes down to grammar, lexical choice, tone, and style of speech, because they can be manipulated. Analyzing the most basic form of communication is enough to hint to investigators of the individual's behavior and endeavors. Think of it as a paper analysis; who is speaking, why do they speak, what are they saying, when are they saying it, where is the conversation taking place and how is the dialogue/narration presented.