Do children better understand adults or themselves? An acoustic and perceptual study of the complex sibilant system of Polish

This paper reports a developmental production-perception study of the three-way Polish sibilant contrast /s, ʂ, ɕ/ in typically developing children (N = 76). Children aged 2;11–7;11 produced words with sibilants in word-medial and initial position. They then identified the same words they produced, and the words as produced by an unknown adult female. Results show higher identification accuracy for adult productions across all ages. Production and perception data suggest that the alveolo-palatal /ɕ/ is acquired first, and that it is differentiated mainly by formant patterns. In the perceptual discrimination task, most errors were found for child-produced /ʂ/, and this persisted into the oldest ages. Early acquisition of /ɕ/ has been observed in other languages and may reflect motoric considerations as well as a focus on formant information in child speech perception. Cue weighting appears to change over age in sibilant-specific ways. While all children weight formants highest for /ɕ/, spectral cues appear to be more important for /s/ and /ʂ/, and reliance on formants may decrease with age. This work contributes to the study of cross-language differences in acquisition, provides an acoustic characterization of child-produced Polish sibilants, and elucidates the acoustic characteristics that children use in perceptual judgments of sibilants.