TL;DR. Stuttering types include three core behaviours — repetitions, prolongations and blocks — plus secondary behaviours like tension and avoidance. Clinically, stuttering may be developmental, neurogenic, psychogenic, or childhood-onset that resolves before adulthood.
The three core behaviours
Almost everything called stuttering is one of three speech patterns. Most people who stutter use all three at different times.
1. Repetitions
Repeating a sound, syllable or short word. Examples:
- "P-p-p-please" — sound repetition.
- "ba-ba-banana" — syllable repetition.
- "the-the-the dog" — single-word repetition.
Repetitions are the most common type in young children. In adults they tend to shorten — fewer iterations, less audible struggle.
2. Prolongations
Stretching a sound out beyond its normal duration. Examples:
- "Mmmmmm-monday"
- "Ffffffish"
The speaker holds an articulator (lips, tongue) in position while voicing or air keeps flowing. From the inside, a prolongation feels like getting stuck on a sound and waiting for the next one to arrive.
3. Blocks
Silent or near-silent halts. The mouth, jaw and respiratory system are set up to produce a word, but no sound comes out. Blocks often involve visible tension — clenched jaw, held breath, neck pull. Many people report blocks as the most physically and emotionally exhausting type of stutter.
Blocks also tend to attract the most secondary behaviours over time, because the sense of being stuck triggers escape strategies.
Secondary behaviours
Almost everyone who stutters develops a layer of secondary behaviours — learned reactions designed to push through, hide or finish a stutter. Common ones:
- Physical tension — clenched jaw, foot tapping, fist clenching, head jerks, eye blinks.
- Word substitution — swapping a feared word for a safer synonym mid-sentence.
- Word avoidance — rerouting the entire sentence around a feared word.
- Situation avoidance — declining phone calls, ordering online or by app to avoid ordering in person, asking a partner to introduce you.
- Filler use — overusing "um", "like", "you know" as starter ramps for difficult words.
- Postponement — pretending to think while you wait for a feared word to feel approachable.
Secondary behaviours stick because they sometimes work — and they often outlast the original disfluency. A common path in therapy is to increase visible stuttering temporarily, so the speaker can drop a secondary layer that's costing more energy than the stutter itself.
Clinical types
Speech-language pathology recognises four clinical types of stuttering, distinguished by when and how they start.
Developmental stuttering
By far the most common type. Appears between ages 2 and 5, during the rapid expansion of language and speech motor skills. About 5–8% of children go through a stuttering phase; most recover by age 8. The roughly 1% who continue into adulthood have persistent developmental stuttering. Its causes are mostly genetic and neurological — see causes of stuttering.
Acquired neurogenic stuttering
Begins suddenly in adulthood after a neurological event: stroke, traumatic brain injury, brain surgery, certain medications (some antiepileptics, antidepressants, dopaminergic drugs). Distinguishing features compared to developmental stuttering:
- Disfluency on any word — including grammatical words like the, a, of.
- Less situational variability — the stutter doesn't fade in singing or talking to pets.
- Often less anticipatory anxiety, because the person didn't grow up stuttering.
Neurogenic stuttering needs neurological evaluation. It sometimes resolves when the underlying cause is treated.
Acquired psychogenic stuttering
Rare. Begins after extreme psychological stress or trauma, accounting for a small minority of adult-onset cases. The disfluency patterns are often unusual and don't resemble developmental stuttering, and it usually responds rapidly to psychotherapy. Diagnosis is by exclusion — neurogenic causes are ruled out first.
Childhood-onset that resolves
Not a separate disorder, but worth flagging. Most preschool stuttering recovers, with or without therapy, by age 8–10. The recovery rate is highest when the family doesn't make the speech a focus of attention or correction. Children who don't recover by age 7 are more likely to have persistent stuttering into adulthood.
Severity
Type is only half the picture. Beyond it, severity varies along several axes:
- Frequency — what percent of words contain a stuttering-like disfluency.
- Duration — how long an average disfluent moment lasts.
- Tension — how much physical effort is visible.
- Reaction — how much the person fears, avoids or feels affected by the stutter.
Clinicians use instruments like the SSI-4 (Stuttering Severity Instrument) and the OASES (Overall Assessment of the Speaker's Experience of Stuttering) to track these dimensions over time. The same word-level frequency can have a very different impact on daily life from one person to the next — which is why the reaction axis matters as much as the others.
What this means for treatment
Therapy works on all of it — but the targets differ:
- For core behaviours, fluency-shaping techniques (prolongation, easy onset, light contact) reduce occurrence.
- For secondary behaviours, stuttering-modification techniques (cancellations, pull-outs) reduce tension and struggle.
- For the emotional layer, CBT, ACT and exposure work reduce avoidance and shame.
The right combination depends on which behaviours dominate. See how to stop stuttering for what daily practice looks like, and treatment for the wider therapy landscape.
