Spectral characteristics of Korean consonants based on a spontaneous speech corpus*

The purpose of this study was to identify the spectral characteristics and patterns of Korean consonants. Consonant-vowel (CV) sequences were selected from the Seoul Corpus, a dialogue speech corpus. Fast Fourier transforms (FFTs) were applied, and the first four spectral moments were calculated: M1 (moment 1; center of gravity), M2 (moment 2; standard deviation), M3 (moment 3; skewness), and M4 (moment 4; kurtosis). Additionally, two slope-related parameters were measured: slope_ltas, which represents the dB difference between two frequency bands, and tilt, which indicates the regression slope. Six linear mixed-effects (LME) models were constructed to examine the effects of gender, manner of articulation, and vowel context on the dependent variables. The relationships between the acoustic variables were also investigated. Finally, binary classification accuracy for distinguishing obstruents from sonorants was calculated. Results indicated that gender differences appeared in obstruents and nasals using parameters other than M4. In distinguishing manners of articulation, the patterns observed in M1, slope_ltas, and tilt differed from those in M3 and M4. M2 showed a distinct trend compared to the other parameters. In terms of vowel context, M1 and M3 exhibited opposite patterns in their values. Furthermore, negative correlations were observed between M1 and M3, as well as between M3 and tilt. Lastly, the overall classification accuracy in distinguishing obstruents and sonorants was 67.67%. The most influential parameters were M3 and tilt.