Anticipatory lip gestures: a validation of the Movement Expansion Model in congenitally blind speakers

In this paper, anticipatory co-articulation of the lip protrusion and constriction gestures is investigated in speakers with visual deprivation. Audio-visual recordings of 11 congenitally blind French speakers producing [V-roundC-roundV+round] sequences were measured with a lip shape tracking system. Lip protrusion and constriction values and their relative timings were analyzed. Results show that despite the reduced magnitude of lip protrusion and constriction area in blind speakers, the timing of the anticipatory gestures can be appropriately modeled by the Movement Expansion Model [from Abry and Lallouache (1995a). Bul. de la Comm. Parlée 3, 85-99; (1995b). Proceedings of ICPHS, pp. 152-155; Noiray et al. (2011). J. Acoust. Soc. Am. 129, 340-349], which predicts lawful anticipatory behavior expanding linearly as the intervocalic consonant interval increases.