Is the pitch of voice lowered (a) by the active contraction of some laryngeal muscles, (b) by the relaxation of those muscles that raise pitch, or (c) by both mechanisms? Evidence will be presented that supports (c). Specifically, electromyographic recordings point to the sternohyoid muscles' participation in pitch lowering, independent of their activity in other speech gestures, e.g., jaw opening. Further, there is evidence of a probable causal correlation between larynx height and pitch of voice (which accounts for the sternohyoids' activity in pitch lowering). Vertical movements in the larnyx, it will be argued, change the pitch of voice by changing primarily the vertical, not the anterior-posterior, tension of the vocal cords. [Research supported in part by the National Science Foundation.]