Static and dynamic spectral characteristics of Swedish voiceless fricatives.

Descriptions of the acoustic characteristics of Swedish voiceless fricatives are scarce and are limited to static measures derived from the speech of a small number of speakers. The current study provides an updated acoustic description of the static (spectral, temporal, and intensity) characteristics of word-initial voiceless fricatives in Central Standard Swedish. In addition, temporal variation of spectral centre of gravity is modelled using a generalized additive mixed model. Results show that fricatives were differentiated in terms of spectral properties, duration, and intensity level, such that sibilant fricatives were generally longer and more intense than non-sibilant fricatives. Spectral centre of gravity differentiated between all places of articulation apart from labio-dental /f/. Gender differences were found for centre of gravity in /s/ but overall, sex/gender differences were small. Dynamic analyses revealed differences in curvature as well as overall level of spectral centre of gravity across the duration of the fricative, associated with place of articulation and mediated by vowel context, fricative duration, and speaker specific patterns. The results from the present study are valuable for future cross-linguistic research, and as reference for investigations concerning children's acquisition of Swedish voiceless fricatives.