2.4.2 Feedback Mechanism

In order to remedy the pronunciation errors, we have adopted different feedback methods for consonants, vowels, and speech rhythm, respectively.

• Articulatory Configuration : For consonants, classification is performed based on the place and manner of articulation to identify the cause of misarticulation, and then the correct articulatory configuration is displayed on the screen, along with pointing to specific production problems.
• Vowel Diagrams : For vowels, the formant frequencies ( , ) of vowel sounds are measured and plotted on the vowel diagram mapped onto the open/close positions on the jaw and front/back on the tongue.
• Contrastive Visual/Auditory Feedback : A rhythmical information is provided by representing mora-timed durations on the screen, and thus the feedback such as rhythmically longer or rhythmically shorter is given to the learners. In addition, auditory confirmation is also provided.