Whispered Mandarin has no production-enhanced cues for tone and intonation

Abstract

It is often assumed, explicitly or implicitly, that speakers generate special cues in whispered tone and intonation to make up for the absence of fundamental frequency. The present study examined this assumption with one production and three perception experiments. The production experiment compared duration, intensity, formants and spectral tilt of phonated and whispered Mandarin monosyllabic utterances with four lexical tones spoken as either statements or questions. For tones, no acoustic properties were found to occur only in whispered but not in phonated utterances. For intonation, some spectral tilt measurements differed between the two phonation types. The two tone perception experiments used phonated and whispered utterances as well as amplitude-modulated noise based on those utterances as stimuli. Results show that once turned into amplitude-modulated noise, phonated and whispered tones had similar identification patterns, indicating that the non-F0 tonal cues in whispers were already in phonated speech. The intonation perception experiment used original utterances as stimuli and showed a substantial drop in overall identification rate and an overwhelming bias towards statement. Thus the spectral tilt differences found in the acoustic analysis were not helpful for intonation perception. Possible reasons for the lack of effective enhancement in whispered speech were discussed.