The effect of time-compression and -expansion on the perception of speech rate differences is investigated. Natural utterances were compared with modified versions time-scaled to the same duration. A set of ten German sentences was produced by one native speaker at slow and fast speed. In a forced choice discrimination task 15 participants were asked to select the faster one of two versions of the same sentence. In the case of low speech rate, versions that had been slowed down were perceived as slower than the corresponding natural utterances, whereas at high speech rates, stimuli with increased speed were judged as relatively faster. The effect turned out to be stronger for the slow stimuli. These findings suggest that the underlying articulatory effort plays an important role in the perception of speech rate.
Bibliographic reference. Pfitzinger, Hartmut R. / Mixdorff, Hansjörg (2013): "Perceiving speech rate differences between natural and time-scale modified utterances", In INTERSPEECH-2013, 277-281.