摘要：The following previously used differential indexes and algorithms for the evaluation of voicing of fricatives are overviewed: HNR ( harmonicsto- noise ratio; Boersma), intensity and temporal parameters of the first harmonic (Stevens, Pirello; etc.). In addition, the supplementary non-differential cues such as duration of a consonant and preceding vowel, and phonation frequency in CàV transition are discussed. The acoustical cues are considered in relation to the articulatory movements and processes of pressure dynamics. It is noted that continuity of phonation is not obligatory cue for identification of voiced fricatives. Structure of low harmonics is characteristic of the spectra of voiced fricatives, in contrast to voiceless fricatives. Based on this difference, a simple LHR method is suggested (low-high-ratio index; i.e., ratio of intensities of low and high frequency bands). The method is applied for the evaluation of voicing of fricatives in standard Lithuanian (prevocalic and intervocalic sibilants are considered). It is estimated that the boundary between the voiced and voiceless sibilants corresponds roughly to LHR = –10 dB. The LHR method is compared to the previous methods and its advantages are discussed. Keywords: fricatives, voicing, phonation, HNR, LHR.
