The Acoustics of Sibilant Fricatives in Urban Hijazi Arabic

This paper examines the spectral characteristics of sibilants s, z, ʃ, and ʒ in the Urban Hijazi Dialect. The analysis investigates intensity, noise duration and center of gravity (COG). These acoustic cues vary based on gender, places of articulation and voicing as reported in other studies. The aims of the study are to fill a gap in the literature of Arabic fricatives and to see whether these characteristics are influenced by places of articulation, voicing or gender in the aforementioned dialect. The dataset includes word-initial fricatives followed by the short vowels ɪ, a, and ʊ. The results suggest that intensity is not very informative as an acoustic cue in differentiating these sibilants. The other two spectral measurements, noise duration and COG, are more reliable. The female speakers produced fricatives with longer durations and higher COG values compared to the male speakers. In addition, for the male speakers, voiced fricatives are shorter in duration and have less acoustic energies compared to the voiceless fricatives. As for the female speakers, voiceless sibilants have longer durations, similar to the male speakers, but COG values are not influenced by voicing. In both genders, the place of articulation influences COG values, where alveolars have higher COG compared to post-alveolars.