Moving Beyond the Plateau with Computer-Assisted Pronunciation Mediation

This paper examines the plateau effect and the role of Computer-Assisted Pronunciation Training (CAPT) in enabling learners to move beyond the plateau. Specifically, the samples and empirical evidence for this study is provided by Study Intonation, a top-down CAPT environment supporting visual display of phrasal intonation in the form of pitch graphs presented for both the model pitch of native speakers and attempts of learners. Utterances of model speakers are grouped by situational context, prosodic forms and mode of feedback. The system largely relies upon concepts of sociocultural theory, such as mediation through the zone of proximal development. With the help of an experimental group of high school students, we use mathematical models to pinpoint the Zone of Proximal Development (ZPD), allowing for delivery of tailored task classification based on syntax and discourse tags. Longitudinal pronunciation assessment supported by dynamic time warping and cross-recurrence quantification analysis is used to locate the ZPD, and provide personalized practice. Preliminary experiments for the current study demonstrate that this approach can help learners in overcoming the plateau effect experienced during the learning process. The reported new findings create further grounds for improving and targeting the CAPT system feedback to learners with respect to their individual achievements and differences in learning styles.