A Wearable Intraoral System for Speech Therapy using Real-Time Closed-Loop Artificial Sensory Feedback to the Tongue

This paper describes a wearable intraoral system for speech therapy using artificial sensory feedback timed with the undesired tongue movement. The system has been implemented as a custom-made palatal retainer, which includes two optical distance sensors and two stimulators to provide error feedback to the tongue. Subjects wore the palatal retainer to test the system performance. By testing the system with phonetic targets /t/ and /d/, we showed that the system was able to detect the tongue movement during pronunciation. The system was also tested to see if it can help a non-native English speaker with Hindi mother tongue to correct the pronunciation of alveolar consonant /t/. The subject was asked to read multiple words containing /t/ consonant repeatedly, with distracting words in between to minimize the involvement of cognition or intentional correction. Test results indicated that the error feedback via stimulation helped the subject to move his tongue forward towards the alveolar ridge in pronouncing /t/. The result justified our hypothesis that intrinsic sensory feedback can be an effective way to train non-native speakers to correct their pronunciation.