Acoustically distinct and perceptually ambiguous: ʔayʔaǰuθəm (Salish) fricatives

ʔayʔaǰuθəm (Comox-Sliammon) is a Central Salish language spoken in British Columbia with a large fricative inventory. Previous impressionistic descriptions of ʔayʔaǰuθəm have noted perceptual ambiguity of select anterior fricatives. This paper provides an auditory-acoustic description of the four anterior fricatives /θ s ʃ ɬ/ in the Mainland dialect of ʔayʔaǰuθəm. Peak ERB_N trajectories, noise duration, and formant transitions are analysed in the fricative productions of five speakers. These analyses provide quantitative and qualitative descriptions of these fricative contrasts, indicating more robust acoustic differentiation for fricatives in onset versus coda position. In a perception task, English listeners categorized fricatives in CV and VC sequences from the natural productions. The results of the perception experiment are consistent with reported perceptual ambiguity between /s/ and /θ/, with listeners frequently misidentifying /θ/ as /s/. The production and perception data suggest that listener L1 categories play a role in the categorization and discrimination of ʔayʔaǰuθəm fricatives. These findings provide an empirical description of fricatives in an understudied language and have implications for L2 teaching and learning in language revitalization contexts.