UC Berkeley

The current dissertation studies how the information conveyed by different speech elements of English, Japanese and Korean correlates with perceptual accuracy. Two well-established information measures are used: weighted negative contextual predictability (informativity) of a speech element; and the contribution of a speech element to syllable differentiation, or functional load. This dissertation finds that the correlation between information and perceptual accuracy differs depending on both the type of information measure and the language of the listener.

To compute the information measures, Chapter 2 introduces a new corpus consisting of all the possible syllables for each of the three languages. The chapter shows that the two information measures are inversely correlated.

In Chapters 3 and 4, two perception experiments in audio-only and audiovisual modalities, respectively, are described. The experiments adopt a forced-choice-identification paradigm. In both experiments, subjects listened to VC.CV stimuli composed of spliced VC and CV chunks, and they were asked to identify the CC sequence. Multiple statistical models are constructed to predict the perceptual accuracy of a CC stop cluster from the associated information measures of relevant speech elements in the listeners' languages.

The estimated models show that high informativity has a generally negative effect on the perceptual accuracy of stops. Functional load shows less consistent correlations with perceptual accuracy across different model specifications, but generally has a positive effect on the perceptual accuracy.

In addition, Japanese listeners show highly consistent results across the two experiments and different model specifications. This contrasts with less consistent results for English and Korean listeners.

The current dissertation provides the first empirical evidence for a significant relationship between informativity and functional load, and between the information measures of speech elements and their perceptual accuracy. Furthermore, it reveals how listeners' native languages affect that relationship, and how the cross-linguistic variation of that relationship may be related to the characteristics of individual languages such as their syllable structures.