Pre-planning in speech was first shown in terms of the control of inhaled air volume [18,19,17,11]: people will inhale more deeply when confronted with longer phrases. This fact implies that at least a rough plan for the utterance has been constructed about 500 ms before speech begins. As another example, Figure 8 in Bellegarda et al. [1] shows that in an upwards pitch motion, the rate of the motion is reduced as the motion becomes longer, presumably to avoid running above the speaker's comfortable pitch range. We take this as evidence for pre-planning of f0 over a 1.5 second range, at least in practiced, laboratory speech.

Greg Kochanski, Chilin Shih 2002-08-03