The present invention relates to a method of synthesizing of a speech signal, comprising: —assigning of a first identifier to a first class of intervals of an original speech signal and assigning of a second identifier to a second class of intervals of the original speech signal, —windowing the original speech signal to provide a number of pitch bells, —processing the pitch bells having the first identifier assigned thereto for modifying a duration of the speech signal, —performing an overlap and add operation on the processed pitch bells.