Nonsegmental Influences on Velum Movement Patterns: Syllables, Sentences, Stress, and Speaking Rate*

Investigations of the motor organization of speech show that if we can identify individual segmental requirements, we can begin to predict the manner in which segments will influence each other in fluent speech. That is, we can model coarticulation as the outcome of temporal overlap (coproduction) among characteristic speech movements for successive segments (e.g., BellBerti & Harris, 1981; Fowler, 1980; Munhall & LMqvist, 1992; Saltzman & Munhall, 1989). Support for a coproduction model has largely been drawn from studies of articulators that shape the oral tract (the lips, jaw, tongue) or of formant frequencies that reflect oral tract shape (cf. BellBerti & Harris, 1981; Boyce, 1988; Fowler, 1980; Ohman, 1966; Saltzman & Munhall, 1989). However, recent work on the velum provides additional strong support for this framework (Bell-Berti & Krakow, 1991a). Studies of velie movement patterns provide evidence for a segmental. level of organization, with n-ary values of velie height ranging from extreme low to extreme high positions. These differences in intrinsic velie height arE:) attributable not only to whether a segment is nasal or not, and whether it is a vowel or a consonant, but to such factors as vowel height, consonant place, manner, and voicing (cf. Bell-Berti, 1980, 1993; Bell-Berti & Hirose, 1975; Clumeck, 1976; Henderson, 1984; Mattisoff, 1975; Moll, 1965; Ohala, 1971, 1975; Ushijima &