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Foreign Accent and Forensic Speaker Identification in Voice Lineups: The Influence of Acoustic Features Based on Prosody
Published on: September 27, 2024
Identification of frequency-shifted vowels
Peter F Assmann1, Terrance M Nearey
1School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, Texas 75083-0688, USA. assmann@utdallas.edu
The Journal of the Acoustical Society of America
|December 3, 2008
Summary
Speech intelligibility remains intact within limits when the spectral envelope is scaled. However, shifts interact with fundamental frequency (F0), impacting vowel identification accuracy across different voices.
Area of Science:
- Speech Perception
- Acoustic Phonetics
- Psychoacoustics
Background:
- Speech intelligibility is generally preserved with spectral envelope scaling.
- The influence of fundamental frequency (F0) on these limits is not fully understood.
- Vowel perception relies on spectral and F0 cues.
Purpose of the Study:
- To investigate the limits of spectral envelope scaling on vowel identification.
- To assess the interaction between spectral envelope scaling and fundamental frequency (F0).
- To examine how these manipulations affect different voice types (men, women, children).
Main Methods:
- Vowels from /hVd/ syllables were processed using the STRAIGHT vocoder.
- Listeners identified processed vowels presented in various spectral envelope and F0 conditions.
- Systematic upward and downward scaling of the spectral envelope was applied.
Main Results:
- Identification accuracy declined gradually with spectral envelope scaling in all voice types.
- Upward shifts impacted children's vowel identification more than adults'; downward shifts affected men's more.
- Coordinated F0 and spectral envelope shifts yielded higher accuracy than opposing shifts.
- Vowel identification was poorest at very high F0, suggesting sparse spectral sampling.
Conclusions:
- Perceptual mechanisms sensitive to the statistical covariation of F0 and formant frequencies likely contribute to vowel identification.
- The interaction between spectral envelope shifts and F0 provides insights into speech processing.
- Findings suggest complex auditory processing beyond simple spectral envelope analysis.
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