Towards letting machines humming in the right way - prosodic analysis of six functions of short feedback tokens in English

We presents prosodic cues, i.e. duration, average F0 (M-F0), F0 slope (D-F0) and spectral center of gravity (CoG), to the functions acknowledgment, continuer, disagreement, surprise, enthusiasm and uncertainty as expressed via short vocal feedback by a professional voiceover artist. The post-hoc tests showed that most functions were expressed with a rather contrastive prosody and in a consistent fashion. Enthusiasm and surprise showed a higher average F0, as well as shorter duration which also acknowledgment showed. The function of continuer showed rising F0 which was contrastive to all other functions. The least contrastive functions, disagreement and uncertainty, only differed in M-F0, while surprise and enthusiasm differed only in CoG.