Perception of place of articulation for plosives and fricatives in noise

This study aims at uncovering perceptually-relevant acoustic cues for the labial versus alveolar place of articulation distinction in syllable-initial plosives {/b/, /d/, /p/, /t/} and fricatives {/f/, /s/, /v/, /z/} in noise. Speech materials consisted of naturally-spoken consonant–vowel (CV) syllables from four talkers where the vowel was one of {/a/, /i/, /u/}. Acoustic analyses using logistic regression show that formant frequency measurements, relative spectral amplitude measurements, and burst/noise durations are generally reliable cues for labial/alveolar classification. In a subsequent perceptual experiment, each pair of syllables with the labial/alveolar distinction (e.g., /ba, da/) was presented to listeners in various levels of signal-to-noise-ratio (SNR) in a 2-AFC task. A threshold SNR was obtained for each syllable pair using sigmoid fitting of the percent correct scores. Results show that the perception of the labial/alveolar distinction in noise depends on the manner of articulation, the vowel context, and the interaction between voicing and manner of articulation. Correlation analyses of the acoustic measurements and the threshold SNRs show that formant frequency measurements (such as F1 and F2 onset frequencies and F2 and F3 frequency changes) become increasingly important for the perception of labial/alveolar distinctions as the SNR degrades.

Research highlights
► This is a psychophysics study of perception of place of articulation in noise.
► In quiet, formant, relative spectral, duration measures are all reliable cues.
► Perceptual thresholds depend on manner, vowel, and voicing-manner-interaction.
► Formant frequency measures become increasingly important as the SNR degrades.