Session Forensic Phonetics:Forensic Phonetics
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| Forensic Phonetics-1 |
SPEAKER IDENTIFICATION USING SELECTIVE COMPARISON OF PITCH CONTOUR PARAMETERS
Natalia Smirnova, Speech Technology Center Alexey Starshinov, Speech Technology Center Ilya Oparin, Speech Technology Center Tatiana Goloshchapova, Federal Service of Drug Control of the Russian Federation Paper File |
| A method of selective pitch data comparison for speaker identification is presented. Pitch parameters of rising and falling nuclear monosyllables and filled hesitation pauses are evaluated for their discriminating ability using F-ratio and EER measures obtained on a 10-male 3-session speech database. “Physical” F0 parameters providing 20%-30% EER in isolation proved more effective than linguistically conditioned ones. Using all parameters in combination produced an EER of 13%. Directions of future research are outlined and the scope of possible method application in forensic tasks is discussed. | |
| Forensic Phonetics-2 |
IMITATED OR AUTHENTIC? LISTENERS' JUDGEMENTS OF FOREIGN ACCENTS
Sara Neuhauser, Friedrich-Schiller-Universität Jena Adrian P. Simpson, Friedrich-Schiller-Universität Jena Paper File |
| This paper presents a perception experiment which investigates (1) whether listeners are able to distinguish between authentic non-native accents and non-authentic (imitated) accents and (2) whether they are able to identify the accents being produced. The results show that native-German-speaking listeners are able to identify (to name) imitated accents better than authentic non-native accents, probably due to the presence or absence of stereotypical patterns being used by the speakers. However, listeners were less able to judge the authenticity of the presented accents which probably can be related to the wide variation in the speakers' ability to imitate an accent. | |
| Forensic Phonetics-3 |
F0 Statistics for 100 Young Male Speakers of Standard Southern British English
Toby Hudson, University of Cambridge Gea de Jong, University of Cambridge Kirsty McDougall, University of Cambridge Philip Harrison, JP French Associates & Department of Language & Linguistic Science, University of York Francis Nolan, University of Cambridge Paper File |
| This paper presents statistical data for the fundamental frequency of 100 young male speakers of Standard Southern British English producing spontaneous speech under cognitive stress. The material comes from the new X database, for which subjects underwent a simulated police interview. The distribution of F0 in a large homogenous group of speakers is of forensic significance since it provides a framework for understanding the significance of F0 measurements in casework. Long-term F0 for the 100 speakers yielded a mode of 102.2 Hz, a mean of 106 Hz and a median of 105 Hz, and had a near-normal distribution. We demonstrate the limitations of F0 as a discriminatory feature for the majority (60%) of our speech group, which fell within a narrow window of 20 Hz. Conversely, we see the forensic implications for recordings where F0 falls outside this window. | |
| Forensic Phonetics-4 |
THE SPEAKER DISCRIMINATING POWER OF SOUNDS UNDERGOING HISTORICAL CHANGE: A FORMANT-BASED STUDY
Gea de Jong, University of Cambridge Kirsty McDougall, University of Cambridge Toby Hudson, University of Cambridge Francis Nolan, University of Cambridge Paper File Additional Files |
| Can patterns of diachronic sound change within a language variety predict phonetic variability useful for distinguishing speakers? Standard Southern British English monophthongs are analysed to test whether individuals differ more widely in their realisation of sounds undergoing change than stable sounds. Read speech of 50 male speakers aged 18-25 is analysed. The ‘changing’ vowels /æ,ʊ uː/ are compared with the stable /iː,ɑː,ɔː/. The data confirm the stability of /iː,ɑː,ɔː/, the fact that /ʊ,uː/ indeed have fronted and that the articulation of /æ/ has become more open. Results from discriminant analysis based on F1 and F2 frequencies, however, do not show a straightforward pattern: no discrete difference is observed between ‘changing’ and ‘stable’ vowels. It is suggested that high variability in some speakers obscures the effect of large between-speaker variability in changing vowels. | |
| Forensic Phonetics-5 |
Forensic Speaker Discrimination with Australian English Vowel Acoustics
Philip John Rose, Australian National University Paper File |
| A large-scale forensic discrimination experiment is described which investigates how well same-speaker speech samples can be discriminated from different-speaker speech samples using acoustic parameters (F-pattern and duration) from Australian English vowels. A multivariate likelihood ratio is used, under both optimum and realistic conditions, as a discriminant function on the five tense and six lax vowels phonemes of 171 male speakers. In 171 target trials and 54,140 non-target trials, comparing samples with just one token per vowel each gave EERs of between 17% and 40%, which dropped to 10% (optimum) and 14% (realistic) when fused. It is also demonstrated that kernel density modeling outperforms normal, and that performance degrades under realistic conditions. | |