By Pickett, Penelope O.
The FBI Law Enforcement Bulletin , Vol. 62, No. 10
With increasing frequency, the term "linguistics" is being heard in the courtroom as linguists bring their expertise to bear during judicial proceedings. Both prosecutors and defense attorneys realize the effectiveness of linguistic testimony which, oftentimes, turns a case around. Because linguistic analysis and testimony can influence investigations and the outcome of cases tried in court, the law enforcement community may benefit from knowing what to expect from the discipline of linguistics.
This article discusses three types of linguistic analysis presented in the courtroom. It shows the differences among the three types by providing examples and explaining the analytical focus of each.
Linguistics, the scientific study of language, is a well-established discipline that interlinks with other disciplines. The 1980's saw the beginning of a wave of linguistic activity in civil and criminal investigations, which swelled into the decade of the 1990's.
Although various linguistic analysis interrelate with judicial matters, the predominant activity centers around three basic types of examination and testimony--author/speaker comparison, author/speaker assessment, and discourse analysis. All three focus on language usage and involve comparison methodology, each from a different perspective.
Linguistic examinations can compare a written communication with a voice communication or a typewritten text with a computer printout. These examinations can also be conducted on two or more written documents or two or more voice recordings.
In the author/speaker comparison process, linguistic examiners analyze and compare applicable elements of the specific communications. These elements include vocabulary selection, syntax, phraseology, spelling, style, format, sentence length, pronunciation, intonation, pitch, rate of speech, voice quality, etc.
When testifying in court, linguistic experts might present computer printouts of word frequency counts and analyses, which show correlations of common word choice or word length between two communications, or words infrequently used by the general population. Experts might also demonstrate comparisons of other items, such as grammatical constructions and errors or speaking characteristics. The following cases illustrate author/speaker comparisons(1) in linguistic examinations.
Case #1: In late 1989, package bombs killed a Federal judge in Alabama and an attorney in Georgia. A linguistic examination by the FBI Laboratory compared the typewritten communiques associated with the bombings to documents known to have been authored by a prime suspect in the case. (Traditional document examination determined that the communiques and the documents were prepared on the same typewriter.) As a result of the linguistic examination, FBI examiners concluded that this suspect was not responsible for the bomb communiques. When the FBI Laboratory received known writings of another suspect, Walter Leroy Moody, Jr., a linguistic examination determined that this suspect most likely authored the bomb communiques. This caused investigators to shift their attention to Moody, who was subsequently identified as the perpetrator and later tried and convicted.
Case #2: A police chief in Pennsylvania received threatening letters in disguised and distorted handprinting.(2) Linguistic examiners were able to compare the threatening letters to letters in normal handwriting written by the suspect. This examination revealed sufficient similarities in vocabulary, grammar, spelling, etc., for examiners to conclude that the suspect most likely composed the anonymous letters. The suspect, the town's former police chief, subsequently confessed.
Case #3: "Dear Sir: I have been involved in espionage for several years...." So began the first in a series of anonymous typewritten letters to the FBI that revealed participation in a spy ring. …