What is the "pitch marker" in the LP-PSOLA algorithm? The LP-PSOLAR algorithm uses a the Linear Prediciton Coding (LPC) to calculate an error vector from a signal. This error vector is used to calculate the pitch markers. What do these pitch markers represent in the original signal in generall? Do they represent a change in fundamental frequency or a change in phoneme (I think both assumptions are wrong)? The following figure depicts the error vector (red) and the signal (green). The second picture depicts an additional example.
The pitch marker indicates the beginning of each cycle of the waveform - or from a more physiological point of view the point at each the periodical motion of the glottis causes a sudden change in air flow.

A stable sound (in pitch and phoneme) will still have a marker every cycle - so these markers do not indicate any change.