People speak almost as fast as possible.   The upper graphs are the signal and pitch contour from a maximum effort pitch warble: the speaker was asked to warble as fast as possible.   She managed to execute one cycle per about 220 ms.   The lower graph shows (on the same time scale), normal Mandarin speech, at a conversational speed.  Here we see a pitch cycle in 400ms.    This is quite normal: most of the time, while speaking, we run our muscles at 50% or more of their maximum speed.   Since we’re pushing the muscles and the attached neural control systems close to their limits, the dynamics of the nerves and muscles will be important.