The Less Meaningful the Understanding, the Faster the Feeling: Speech Comprehension Changes Perceptual Speech Tempo

The perception of speech tempo is influenced by both the acoustic properties of speech and the cognitive state of the listener. However, there is a lack of research on how speech comprehension affects the perception of speech tempo. This study aims to disentangle the impact of speech comprehension on the perception of speech tempo by manipulating linguistic structures and measuring perceptual speech tempo at explicit and implicit levels. Three experiments were conducted to explore these relationships. In Experiment 1, two explicit speech tasks revealed that listeners tend to overestimate the speech tempo of sentences with low comprehensibility, although this effect decreased with repeated exposure to the speech. Experiment 2, utilizing an implicit speech tempo task, replicated the main findings of Experiment 1. Furthermore, the results from the drift-diffusion model eliminated the possibility that participants' responses were based on the type of sentence. In Experiment 3, non-native Chinese speakers with varying levels of language proficiency completed the implicit speech rate task. The results showed that non-native Chinese speakers exhibited distinct behavioral patterns compared to native Chinese speakers, as they did not perceive differences in speech tempo between high and low comprehensibility conditions. These findings highlight the intricate relationship between the perception of speech tempo and the comprehensibility of processed speech.