Simultaneous registrations of air flow, air volume, and pre-tracheal vibration were performed during the initial period of vowel production with different physiologic types of vocal initiation. Measurements included the amount of air consumed during the initial 200 msec of phonation, air leakage before vocalization, and rise time of pretracheal vibration. Soft initiation was characterized by a long rise time and a small amount of air consumption. Hard attack was associated with a short rise time and considerable air usage. The breathy vocal attack showed a dissimilar pattern suggesting a basic physiologic difference.