This paper examines whether lip protrusion is affected by initial strengthening of rounded vowels in French. Three speakers produced sentences containing the vowels /i, e, E, a, y, o, oe, u, o, O/ at the beginning of different prosodic constituents: Intonational Phrase (IP), Accentual Phrase (AP) and Word (W). Using video and Qualisys motion capture data, three parameters (lip protrusion, area/lip protrusion and lip protrusion/area) are compared to characterize the labial configuration, first between [.round] and [+round] vowels, then within [+round] vowels. These three parameters are found to discriminate between [+/.rounded], to reflect some within category distinction and to show speaker-specific labial patterns. Concerning the effect of prosodic boundary, only the combined measurement of lip protrusion/area reveals a speaker dependent effect on prosodic boundaries. Two speakers out of three show a tendency to decrease lip protrusion/area in IP initial position for back rounded vowels (/o/ and /O/) and for /y/. Prosodic boundary effects are discussed in terms of feature enhancement.
Bibliographic reference. Georgeton, Laurianne / Audibert, Nicolas (2013): "Is protrusion of French rounded vowels affected by prosodic positions?", In INTERSPEECH-2013, 3547-3551.