A New Artificial Palate Design for the Optical Measurement of Tongue and Lip Movements

Electropalatography (EPG) is a well-known and established technique to measure the detailed time-varying contact pattern between the tongue and the hard palate. For EPG, the speaker wears an artificial palate in his mouth, which contains multiple electrodes (contact sensors) to register contact with the tongue. A related technique, albeit less known, is glossometry or optopalatography (OPG). For OPG, the speaker wears an artificial palate that contains optical distance sensors instead of contact sensors. These sensors allow to measure the distance between the palate and the tongue at multiple points and so to reconstruct part of the tongue shape, regardless of whether the tongue is touching the palate or not. Despite this advantage for the analysis of speech movements compared to EPG, the technique was not widely adopted. One of the main reasons is the high costs of manufacturing the corresponding palates, which must be individually made for each speaker. This study presents a new palate design for OPG that greatly reduces the cost and time needed to make the palates. Furthermore, the new design allows the additional measurement of the upper lip position. The effectiveness of the palate design is demonstrated by measurements of vocalic tongue shapes and lip positions.