Lingual velocity and onset of voicing

The timing of tongue movements was studied in relation to oral release and onset of voicing, using pulsed-echo ultrasound. The stimuli were CV syllables, produced at two speech rates and different stress patterns. Relationships between the timing of maximum velocity on tongue lowering, oral release, and voice onset were examined. The interval from oral release to the point of maximum lowering velocity was essentially constant across differences in speech rate, voicing, and vowel height, though estimates differed for stressed and unstressed vowels. For unstressed vowels, peak lowering velocity lagged oral release by approximately 5 ms; for stressed vowels the delay was about 35 ms. The interval from the point of maximum velocity to voice onset was highly correlated with VOT. Further, for stressed vowels, VOT was inversely related to the maximum velocity of tongue lowering and to the distance to the point of maximum velocity from linguo-palatal contact. As reported by others, VOT varied with speech rate, consonantal voicing, and vowel height.