Types of Stuttering: Repetitions, Blocks, Secondary Behaviors, and Covert Stuttering
Stuttering shows up as repetitions (“b-b-boy”), prolongations (“sssometimes”), and blocks — silent, stuck moments — often with tension. People may also show secondary behaviors like eye blinks, or avoidance like switching words. ASHA separates overt from covert stuttering. Here is what each looks like.
The core stuttering behaviors
| Behavior | What it sounds like |
|---|---|
| Whole-word repetition (one-syllable words) | “Why-why-why did they go there?” |
| Part-word or sound/syllable repetition | “Look at the b-b-boy” |
| Prolongation | “Sssssometimes we stay home” |
| Block | A silent pause, or being unable to start a sound |
| Tension or struggle | Words pushed out with visible physical effort |
Signs of overt stuttering (ASHA Practice Portal).1
ASHA notes that the frequency, duration, and tension of overt stuttering can fluctuate from day to day and with the speaking situation.1
Typical disfluency is a different pattern
ASHA’s comparison chart separates typical disfluency — multisyllabic whole-word and phrase repetitions, interjections, and revisions, with no tension, secondary behaviors, or frustration — from stuttering, which features sound or syllable repetitions, prolongations, and blocks, often with tension, secondary behaviors, negative reactions, and avoidance. Children who stutter also have typical disfluencies.2
Overt vs. covert stuttering
ASHA describes overt stuttering as stuttering openly with minimal attempts to hide it, and covert stuttering as hiding or trying to hide it through avoidance and escape behaviors. The same person may be overt at home and covert at work. Concealment can start in the preschool years, and efforts to conceal stuttering are associated with greater adverse impact, psychological distress, and reduced quality of life.1
NIDCD also distinguishes developmental stuttering, which begins in childhood and is the most common form, from neurogenic stuttering, which can follow a stroke, head trauma, or other brain injury.3
About SpeechStep
SpeechStep is practice for speech sounds and does not assess or treat stuttering. A speech-language pathologist can evaluate fluency.
Frequently asked questions
What are the main types of stuttering behavior?＋
ASHA lists repetitions of whole one-syllable words (“why-why-why”), part-word or sound repetitions (“b-b-boy”), prolongations of sounds (“sssssometimes”), blocks (silent pauses or being unable to start a sound), and words produced with excess physical tension or struggle.
What is a stuttering block?＋
A moment when sound stops — an inaudible or silent pause, or an inability to start a sound — often with visible tension. ASHA lists blocking among the signs of overt stuttering.
What are secondary behaviors in stuttering?＋
Behaviors that accompany moments of stuttering: body movements such as head nodding or fist clenching, facial movements such as eye blinking or jaw tightening, and unexpected sounds such as throat clearing.
What is covert stuttering?＋
Stuttering that a person hides or tries to hide using avoidance and escape behaviors — for example, switching words or talking around a feared word. ASHA notes that efforts to conceal stuttering are associated with more adverse impact and psychological distress.
Put this into practice today
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References
3 sources from authoritative bodies. Last reviewed October 2026.
- 1.ASHAFluency Disorders — Practice Portal page.
- 2.ASHACharacteristics of Typical Disfluency and Stuttering — Practice Portal resource.
- 3.NIDCDStuttering — Fact sheet.