站点首页 网址导航 英文资源 法律英语 网主其人 学人论坛

  您现在的位置:首页 >> 专业期刊 >> 言语、语言与法律国际杂志—法律语言学
h

Volume 9, number 1 (August 2002)


Francis Nolan

Intonation in speaker identification: an experiment on pitch alignment features

ABSTRACT While long-term fundamental frequency statistics have been shown to be useful in discriminating speakers, relatively little attention has been paid in work on speaker characterization to intonation as a linguistically and phonetically structured phenomenon. To help redress the balance, this article presents the results of an experiment on between-speaker differences in linguistically specified intonational events. An autosegmental-metrical model of intonation is assumed which uses H (high) and L (low) targets as its primes. Since the pitch of the events corresponding to these targets is highly variable due to factors such as within-speaker variation in pitch range (or ‘pitch span’), this study investigates as a source of speaker discrimination the temporal alignment of these intonational events with segmental events. A limited degree of discrimination is achieved in highly controlled materials. Of theoretical interest is that definable pitch events lying between H and L targets show more potential for betweenspeaker discrimination than the targets themselves.
Full Text  


R.Rodman et al.

Forensic speaker identification based on spectral moments

ABSTRACT A new method for doing text-independent speaker identification geared to forensic situations is presented. By analysing ‘isolexemic’ sequences, the method addresses the issues of very short criminal exemplars and the need for open-set identification. An algorithm is given that computes an average spectral shape of the speech to be analysed for each glottal pulse period. Each such spectrum is converted to a probability density function and the first moment (i.e. the mean) and the second moment about the mean (i.e. the variance) are computed. Sequences of moment values are used as the basis for extracting variables that discriminate among speakers. Ten variables are presented all of which have sufficiently high inter- to intraspeaker variation to be effective discriminators. A case study comprising a ten-speaker database, and ten unknown speakers, is presented. A discriminant analysis is performed and the statistical measurements that result suggest that the method is potentially effective. The report represents work in progress.
Full Text  


Gea de Jong and Terry Honess

The perception of speed-modified recordings

ABSTRACT The overall quality of audio tapes may be affected by such factors as background noise and the intensity of the signal, or whether the recording was made at the correct speed. The last would affect the speaking fundamental frequency (SFF), and therefore perceived pitch, and phonetic characteristics of the speech sample. Listeners’ skills regarding the recognition of recording speeds that had been manipulated are investigated here. It was found that a majority of correct identifications of speed manipulation is only achieved when the speed is –6% or +6% off the correct speed in an experimental procedure that compared deviations of 3, 6 and 9%. Judging samples that are played at higher speeds is easier than those played at lower speeds. Expert listeners did not perform any better than naive or trained listeners. However, they were more cautious and were more often correct when very confident about their judgments.
Full Text  


Gea de Jong, Paul Newis† and John Hunt

The effects of repeated copying and recording media on intelligibility

The increasing use of MiniDisc technology for audio harvesting by law enforcement agencies gives some cause for concern. The reasons for its use are understandable: the kit is small, cheap, light and easy to use. However, there are disadvantages when compared to some of the existing technologies, due to the use of bit reduction techniques. In order to demonstrate the potential problems associated with MiniDisc technology, a two-factor design experiment was set up in which listeners were asked to listen to representative lists of words, contaminated with speech babble. The two factors of interest were (1) type of medium (e.g. analogue tape, MiniDisc) and (2) the generation copy. It was found that the copying process of MiniDiscs affects the quality of the signal in an unpredictable manner: it could improve but also deteriorate the signal. Quality could be deteriorated but intelligibility could have improved. The effects of different types of MiniDisc equipment vary due to different compression techniques. In addition, the superior quality of DAT and the inferior quality of analogue tapes was confirmed.
Full Text  


Francis Nolan

The ‘telephone effect’ on formants: a response

This article is a response to Hermann Künzel’s article ‘Beware of the “telephone effect”: the influence of telephone transmission on the measurement of formant frequencies’ (Forensic Linguistics 8(1), 80–99). There, he shows convincingly that the evaluation of formant frequencies, notably F1, is affected by the band-pass filter effect of telephone transmission. This response does not question his data, or cast doubt on the general lesson to be drawn on the need for caution in estimating formant frequencies from telephone speech, or engage with the issues of dialectological methodology with which he is in part concerned, but it does challenge the apparent strength of the conclusion he draws for forensic speaker identification (FSI). His conclusion could be read as endorsing a complete exclusion of formants from the FSI process, and his article will, I fear, be misinterpreted by some as justification for setting aside a valuable source of speaker-characterizing acoustic information in FSI.
Full Text  


Hermann J. Künzel
Rejoinder to Francis Nolan’s ‘The “telephone effect” on formants: a response’
Full Text  


Robert Rodman

CASE REPORT: Linguistics and the law: how knowledge of, or ignorance of, elementary linguistics may affect the dispensing of justice

Ignorance of elementary linguistic concepts may have a bearing on justice. This thesis is drawn from the conviction appeal of a Haitian-born American sentenced to prison for 12 years for dealing cocaine. The verdict was based in part on a surreptitious recording of the drug deal. Although the drug dealer on the tape spoke a dialect of American Black English, and the defendant speaks English with a Creole accent, the State persuaded the jury that the Haitian disguised his voice by purposefully dropping his accent. His ability to perform this feat was attributed in testimony to the fact that he had been an interpreter for the United States Army in Haiti, and was therefore a linguist, and therefore understood ‘sound change’, and therefore could disguise his voice by dropping his foreign accent. This absurd chain of non sequiturs, and the resulting miscarriage of justice, is the result of linguistic naiveté, and would not have occurred if the court knew that an interpreter is not necessarily a linguist, and that sound change refers to the historical development of languages.
Full Text  


A. P. A. Broeders, Tina Cambier-Langeveld and Jos Vermeulen
CASE REPORT: Obtaining reference material in a case with two unknown speakers: getting two suspects on speaking terms
Full Text  


A. P. A. Broeders, Tina Cambier-Langeveld and Jos Vermeulen
CASE REPORT: Arranging a voice lineup in a foreign language
Full Text  


Michael Jessen
CONFERENCE REPORT: Annual Meeting of the International Association for Forensic Phonetics, Paris, 4–6 July 2001
Full Text  


PhD abstracts
Full Text 


Book Reviews
Tim Grant, Pamela S. Morgan, Susan Berk-Seligson


Book reviews
Full Text 
Forensic Linguistics is published by the University of Birmingham Press. 
User: WEIMING LIU
Session: 21555

.

 

西北政法大学外国语学院刘蔚铭教授创建与维护

2002-05-062008-01-25