Hey I know an area of research about this.

by R. Proffitt Moderator - 3/4/12 3:03 PM

In Reply to: Multimedia computing by ramcmuth

The research was on "Speaker-specific variability of Phoneme Durations". It was very good and the conclusion was that the variation of the length of the phonemes did indeed change with the speaker!

http://www.youtube.com/watch?v=NeK5ZjtpO-M really shows it.