Velar movement assessment for speech interfaces: An exploratory study using surface electromyography

Abstract

In the literature several silent speech interfaces based on Surface Electromyography (EMG) can be found. However, it is yet unclear if we are able to sense muscles activity related to nasal port opening/closing. Detecting the nasality phenomena, would increase the performance of languages with strong nasal characteristics such as European Portuguese. In this paper we explore the use of surface EMG electrodes, a non-invasive method, positioned in the face and neck regions to explore the existence of useful information about the velum movement. For an accurate interpretation and validation of the proposed method, we use velum movement information extracted from Real-Time Magnetic Resonance Imaging (RT-MRI) data. Overall, results of this study show that differences can be found in the EMG signals for the case of nasal vowels, by sensors positioned below the ear between the mastoid process and the mandible in the upper neck region.