Forensic linguistics is the branch of linguistics in the service of criminology and law enforcement. A forensic linguist studies evidence from the realms of speech (as found in voice recordings or phone transcriptions) and language (as found in e-mails, chat, text messages; or handwriting found in notes, letters, contracts, wills etc.) with the aim of corroborating or confuting a set of crime-related hypotheses.
If you are a parent of a teenage child, I would urge you to consider watching this troubling video with your child, and to follow up on it with a discussion of the dangers of social networks.Dr. Jochen L. Leidner
Describes the texts the facebook killer sent to Ashleigh Hall to draw her into a trap. Pretending to be 17 year old 'Peter Cartwright', the killer, who was actually 32 year old Peter Chapman, lured Ashleigh into his car before killing her. This video explores the linguistic tricks he used to achieve this terrible goal. Essentially, the video shows that Peter Chapman is a linguistic master criminal: he has full mastery not only of language, but how to exploit it to gain what he wants.