ISCA Workshop on Plasticity in Speech Perception (PSP2005)
Senate House, London, UK
Previous research presents conflicting evidence about the relevance of formant transitions for fricative identification. We investigated whether listeners' attention to formant transitions is language-dependent, and is determined by the presence of spectrally similar fricatives in the language's phoneme repertoire. We run a series of phoneme-monitoring experiments in which native Dutch, German, English, Spanish, Polish, and Italian listeners detected a target fricative, /s/ or /f/, in nonwords. Misleading formant transitions were introduced to half of the words by cross-splicing. The listeners showed language-specific patterns of fricative perception: Dutch and German listeners were not affected by the misleading formant transitions, whereas Spanish, English, Polish, and Italian listeners missed more fricatives surrounded by misleading than by correct formant transitions. Both Dutch and German contain no spectrally similar fricatives. There is thus no need for Dutch and German listeners to pay attention to the formant transitions, since all fricatives can be distinguished on the basis of their spectral characteristics only. Spanish and English, both languages with the spectrally similar labiodental and dental fricatives in their phoneme inventory, paid attention to the formant transitions especially when detecting the labiodental /f/. Polish listeners paid attention to formant transitions, especially for /s/. The alveolar sibilant has been shown to be a very robust fricative and less confusable in other languages. As Polish contains postdental, alveolar and alveolopalatal fricatives, the perceptual distinctiveness of these sibilants might be reduced. We conclude that listeners' sensitivity to formant transitions for fricatives is determined by the presence of spectrally confusable fricatives in their native languages. This listening strategy is restricted to the confusable fricatives, and is not generalized to spectrally more distinct fricatives. Also the Italians show sensitivity to formant transitions, even though Italian has few distinctive fricatives. However, there is regional variation in the production of fricatives and there is lenitization of stops. This results in spectrally similar fricatives of allophonic status carrying extralinguistic information. Apparently, as a consequence Italian listeners show sensitivity to formant transitions. An additional experiment with only Dutch, German, and Spanish listeners shows that the results are independent of the exact realization of the phonemes or the native language of the speaker. The sensitivity to acoustic cues does not adapt to the requirements of different phoneme realizations, but is determined by the native language, and this seems to limit plasticity in speech perception.
Bibliographic reference. Wagner, Anita / Ernestus, Mirjam (2005): "Listeners' sensitivity to formant transition is adapted to the requirements of their native language", In PSP2005, 97 (abstract).