What Is Stuttering? Stuttering  is a natural variation in speech  in which the timing and flow of spoken language include moments of repetition, prolongation, or blocking  of sounds and words. These moments are simply examples of the many ways humans produce speech. Commonly Observed Features Repetitions  – repeating sounds, syllables, or words (e.g., “I-I-I want to go”). Prolongations  – stretching out a sound (e.g., “ssssun”). Blocks  – pauses where speech momentarily stops