Stuttering is a speech difference with a biological source and characterized by primary and secondary characteristics, or behaviors.
This article refers specifically to developmental stuttering, as opposed to acquired stuttering. Developmental stuttering typically develops during childhood and continues, for some, into adulthood. Stuttering is also known as Stammering, with the different terminology being used in different countries.

Primary Characteristics

The primary characteristics of stuttering are a manifestation of the biological source of stuttering. They consist of:

• - Prolongations: where sound is stretched out (e.g., "lllllike this")
• - Repetitions: where syllables or sounds are repeated (e.g., "li-li-like this")
• - Blocks: where the speaker cannot get any sound out at all (also known as silent blocks)

Secondary Characteristics

The secondary characteristics of stuttering include struggle and avoidance behaviors such as:

• - Physical tension in the body, such as a tense jaw, neck, or abdomen
• - Use of filler words and sounds, such as "um," "err," "like," or "you know"
• - Involuntary body movements like head jerks or tic-like behaviors
• - Various types of avoidance, such as word substitution or avoiding speaking altogether

Stuttering and Struggle

The key to understanding stuttering is knowing the difference between stuttering and the struggle with stuttering.
The secondary behaviors are attempts to avoid or hide stuttering and result from stigma. In most cases of so-called "severe" stuttering, the severity comes more from the struggle than the stuttering itself.
It is important to distinguish between primary and secondary behaviors because:

• - Understanding the situation helps us choose the best way to deal with it
• - Misidentifying the issue can lead to ineffective or inappropriate treatment
• - Recognizing the cause of suffering is key to resolving it

The Biological Basis of Stuttering

Research shows that stuttering is biological in nature. It stems from neurophysiological differences that affect speech motor timing and initiation.

• - There are both functional and structural brain differences in people who stutter (PWS)
• - There are genetic components, though not all cases are hereditary
• - Dopamine levels have been linked to stuttering

Note: These neurological differences only affect speech control — not intelligence or other capabilities.

Statistics

• - About 5% of preschool children experience some phase of stuttering, with 75–80% recovering naturally
• - Roughly 1% of adults stutter, though UK data (2021) suggests closer to 2%
• - The male-to-female ratio is about 4:1
• - Stuttering occurs across all countries, languages, and cultures

Difference, Not Defect

Stuttering should be seen as a difference, not a defect. This perspective shapes how we treat those who stutter and how we approach stuttering itself.

• - The problem is not the stuttering itself
• - The real problem lies in the social stigma and prejudice against PWS

The Role of the Listener

• - Just listen to what the person is saying — not how they say it
• - Avoid giving advice like “slow down” or “just breathe” — it’s unhelpful
• - Don’t finish their words or sentences — let them speak at their pace
• - If you don’t understand, politely ask for clarification

Some Common Myths About Stuttering

• - Stuttering is not caused by emotional or psychological problems
• - Stuttering is not related to intelligence
• - Stuttering is not due to low self-confidence or self-esteem
• - Stuttering is not caused by stress — though stress can make it worse
• - Stuttering is not the result of childhood trauma — although trauma may trigger it in predisposed individuals
• - Stuttering does not define the person — it is only one part of who they are