Speech analysis has a type called vocal stress analysis which detects stress in the form of micro-tremors in a person's speech. It is important to note that vocal stress analysis is equivalent to the polygraph. Both polygraph and stress have the common problem of not being able to report deception. Despite this, speech analysis is apparently used by both the Federal Bureau of Investigations and the United States Central Intelligence Agency. The fact that each person has a unique voiceprint makes it theoretically possible to identify a speaker. This can be achieved through acoustic analysis of intonation meters, vowel height and length. When the pairs of spectrographs showing the suspected speaker and the known speaker saying similar words match, the speaker can be easily identified (Olsson 2004, p. 71). The fact that voice stress analysis relies on eye comparison is a big problem. . Another problem concerns the variation that occurs within the same speaker. It is reported that saying the same sentence a hundred times in a row does not produce two identical pronunciations. However, some countries such as the United Kingdom prefer auditory analysis to the acoustic method. In auditory analysis, speech samples are transcribed phonetically. This analysis is important because it allows analysts to identify idiosyncratic features such as speech disorders and unusual realization of phonemes. Additionally, analysts might feel the need to profile the social and regional identity of the speaker. Speech analysis today considers the mixed method to be the most precise and reliable. It can find its application in situ...... middle of article ...... and textual analysis (Gibbons 2003, p. 26). Works cited Coulthard, M, & Johnson, A 2007, An introduction to forensic linguistics: Language inevidence, Routledge, New York. Gibbons, J 2003, Forensiclingings: an introduction to language in the justice system, Blackwell Pub, Malden. Gibbons, J and Turell, TM 2008, Dimensions of forensic linguistics, John Benjamins Publishing Company, Amsterdam. Jordan, SN 2002, Forensic linguistics: the linguistic analyst and expert witness of linguistic evidence in criminal trials, Biola University, La Mirada .McMenamin, GR, & Choi, D 2002 Forensic Linguistics: Advances in Forensic Stylistics, Crc Press, Boca Raton.Olsson, J 2008, Forensic Linguistics, Continuum, London.Olsson, J 2004, Linguistics Forensic Science: An Introduction to Language, Crime and the Law, Continuum International Publishing Group, London .