Stammering, also sometimes referred to as stuttering, is a relatively common speech problem affecting approximately 1-3% of the world's population.

What is a Stammer?

Stammering, sometimes called stuttering/dysfluency is what we call the interruptions to the smooth forward flow of speech.  Many factors contribute to the development and maintenance of stammering.  It occurs across all areas of society.  It usually starts in childhood, between the ages of 2-5 years, and can persist into adulthood.  There is a lot of variability in how people stammer and some of the more common features are:

  • Repeating whole words (e.g. “and and and I went”)
  • Repeating sounds (e.g. “wh-wh-wh-what”)
  • Prolonging a sound (e.g. “pass mmmmme the sssssssalt”)
  • Blocking on sounds or words (e.g. when nothing comes out)

Stammering is variable, meaning that it may be more or less noticeable across different times and situations.  While there is no cure for stammering, there are supports available to reduce the negative impact it has on a person’s life and increase positive attitudes.  

Adopted strategies to deal with a stammer

Some people who stammer develop different ways of coping with this which can sometimes be referred to as ‘secondary behaviours’.  These can include:

  • Facial grimacing
  • Physical tension, particularly in the face, neck and shoulders
  • Head and body movements
  • Avoiding certain words
  • Changing what they are going to say
  • Avoiding situations
  • Negative feelings, such as anxiety, embarrassment or fear

Some of these strategies can lead to increased tensions and in the long term may result in pain across a person’s face and neck.  Therapy can offer different ways of coping with a stammer that may be more useful in the long term, as well as supporting you to be able to say what you want to say when you want to say it.  

Who is affected?

  • Research suggests that around 1-3% of the world’s population have a stammer
  • Approximately 8% of children will go through a period of stammering, for the majority of children this is developmental stammering and it will resolve naturally 
  • At the age of onset around the same percentage of boys and girls will start to stammer.  By around 7yrs around 4 times as many boys will persist in stammering compared to girls.
  • There can be a link to a family’s history of stammering 
  • It occurs in all cultures
  • Stammering can coincide with other communication difficulties 
  • It has no bearing on a person’s intelligence 

Developmental stammering

Lots of preschool children will go through a period of stammering between the ages of 2-4 years old.   This tends to occur when children go through a language spurt and need more time to access the words that they want to use.  It can also happen when they are making quick developments in other physical or mental skills.  If the stammer gradually resolves it is often termed a ‘developmental stammer’. Research shows that 4 out of 5 children will develop out of their stammer, there are a number of indicators that would make it more likely that stammering will persist.  Please contact your local speech and language therapy department for more information and advice. You can find some information and advice to help you here.

Acquired stammering 

In rare cases, older children and adults can develop an acquired or late-onset stammer.  This can be caused by:

  • Stroke
  • Head injury
  • Neurological conditions, such as Parkinson’s disease
  • Side effects of medication or drugs
  • A result of trauma

Acceptance & Commitment Therapy (ACT):

Generally accepting the stammer and committing to improving or controlling your speech.  It is a form of Cognitive Behaviour Therapy (CBT).

Acquired (idiopathic or late onset) stammering:

A relatively rare form of stammering mainly occuring in older children and adults as a result of a head injury, stroke or a progressive neurological condition. It may also be caused by certain drugs or medication, or psychological or emotional trauma.

Block/Stammering modification:

A type of therapy that focuses not on the person becoming more fluent but helping the person to stammer more fluently

Camperdown Programme:

Behavioural therapy programme to help adults & older children who stammer to speak more fluently by learning prolonged speech: easy, flowing, smooth production of continuous speech. Developed by the Australian Stuttering Research Centre.


Exhibited by fluent people and is often referred to as stammering.  Characterised by a rapid/irregular speaking rate.  Children who are identified as cluttering are often difficult to understand due to the rapid or jerky flow of speech.

Cognitive Behaviour Therapy (CBT):

A type of talking therapy that helps patients understand the thoughts & feelings around their behaviours.  CBT is often used to treat anxiety, depression and phobias – speech & language therapists often integrate this into speech therapy.

Costal breathing:

A breathing method which uses the costal diaphragm to control breathing. Also known as diaphragmatic breathing. The technique taught on The Starfish Project and The McGuire Programme.

Covert/interiorised/hidden stammering: 

A person with a covert stammer will likely have high levels of fluency and use strategies (coping techniques/avoidance behaviours) to hide their stammer.


A term used in speech therapy.  Generally allowing the PWS (Person Who Stammers) to reduce the fear or anxiety around stammering and thereby allowing the person to gain more control over their stammer.

Developmental stammering:

The most common type of disfluency, and described as a normal part of childhood, will normally start between the ages of 2 and 5. The majority of children who display developmental disfluency at this young age will not go on to develop a stammer.


Any irregularity in the fluent flow of speech – i.e. irregular speech patterns or breaks in speech – generally affecting most of the population!


Created by Dr Joseph Sheehan to describe the effects of stammering – above the iceberg, the parts you can see i.e. jerky head movements, tension in the facial muscles or repetition of speech, and below the iceberg, the hidden effects of stammering i.e. anxiety, panic, shame or guilt etc.

Lidcombe Programme:

For parents of a young child who stammers (normally under 6) carried out with the guidance of a speech and language therapist.


The basic human ability to just be present in the moment.

Neuro-linguistic Programming (NLP):

The practice of understanding our thinking, behaviours and feelings.


An acronym meaning:

‘People/Person Who Stammer(s)/Stutter(s)’.

A term often used in research papers and by those who stammer/stutter.


Acronym meaning ‘Speech & Language Therapist’ (UK) or ‘Speech & Language Pathologist’ (US).


Term used for stammering in America, Australia and New Zealand.

Stuttering Hexagon:

“The Stuttering Hexagon is a comprehensive model of stuttering originated by John C. Harrison in order to adequately characterize the chronic blocks of adult stuttering.”  (  Redefining Stuttering)

Voluntary stammering:

Stammering on purpose. PWS use it to help them become desensitised to stammering.

There are different speech and language therapy approaches available on the NHS that can help people who stammer to speak more easily and address issues that can come from having a stammer. 

There are also a number of other approaches and details of these can be found here.

For NHS speech therapy, you’ll work with a therapist to choose a suitable plan tailored to your child or you.

This may involve:

  • Creating an environment where your child feels more relaxed and confident about talking.
  • Strategies to increase fluency and develop communication skills.
  • Working on feelings associated with stammering, such as fear and anxiety.
  • Electronic devices to reduce stammering are also available and can help some older children and adults.

If you are looking for further information or advice please see the links in the Resources section of our website.