Articulatory and acoustic cues of softness in consonants of s- and z-type

This paper aims to identify reliable acoustic cues differentiating hard and soft consonants based on their wave forms and spectrograms obtained during their isolated pronunciation and to compare the acoustic cues to the previously explored articulatory cues. The author challenges the traditional view that softness is solely achieved due to palatalization (raising the middle part of the tongue to the hard palate) and proposes a hypothesis emphasizing the role of laryngeal mechanisms including inherent coarticulation of the vocal folds and larynx. The paper presents experimental results from analyzing two pairs of consonants ([s]–[sʲ], [z]–[zʲ]) recorded with fixed supralaryngeal articulator positions. The analysis of wave forms and spectrograms revealed significant differences in amplitude and spectral density between hard and soft consonants as well as in contrasting zones in mid and high frequency ranges. The findings confirm that softness is an inherent feature determined by the laryngeal adjustments. This discovery offers new criteria for automatic speech recognition and comparative linguistic studies.