A young girl on a sofa holding a toy, with her mother sitting next to her
Jasmine & mum Heather

What Is Stammering?

Learn all about stammering in children and adults. Find out the definition and meaning, and what we know about its causes.

Forget any preconceptions you may have about stammering. People don't stammer because they're nervous or less intelligent. Or because of anything parents have done. But what exactly do we know? Why does stammering start? Will it stop?

On this page: 

What does stammering look and sound like?
When does stammering start?
What causes stammering?
Do people stop stammering?
Is stammering different to stuttering?
What else do we know?
Support & more information

What does stammering look and sound like?

Stammering (also known as stuttering) is when a child, young person or adult:

  • repeats sounds or words. For example "My name is J-J-J-J-John".
  • stretches or prolongs sounds. For example "Can you read me a ssssssstory?".
  • has a silent block where a sound gets stuck. For example "---------Can I have…". A block could last for a few seconds or it could last longer. 

Everyone does these things occasionally. But for people who stammer they happen more often, sometimes nearly every time they speak. Stammering can happen at any point in a sentence. People might do just one of the things above or they might do more.

Other behaviours

If someone is finding it hard to get sounds out, they might also:

  • appear tense in their mouth, face or body
  • have their breathing restricted 
  • close their eyes or look away
  • use other parts of their body to help get a word out or release tension. For example they might tap their fingers, jerk their head or stamp their feet 
  • say "um" or "er" to help them launch into words they find more difficult to say. 

For some, there might not be any tension at all. Everyone's stammer is unique and everyone stammers differently. It's normal for stammering to fluctuate. People can stammer less on some days or in certain situations, and more in others. Lots of people find they stammer more when they are tired.

Stammering isn't always obvious

A lot of people might use ways to minimise their stammer some or all of the time. So, it might not always be obvious that they stammer. Find out more on our Covert Stammering page.

When does stammering start?

Stammering most commonly starts in early childhood, usually around the ages of 2 to 5. In some children it can start later, and it sometimes first appears in adulthood. See below for more.

What causes stammering?

We don't yet fully know why people stammer. But we do know some things, which we explain below.

Causes when stammering starts in childhood

Young children often start stammering when speech and language skills are rapidly developing. This is called 'developmental stammering'. We don't know exactly why it happens. But recent research is showing that it is neurological. This means that the brain coordinates the speech muscles in a slightly different way that results in stammering.

We also know stammering has a genetic link, meaning it can run in families. It can be hereditary. Research suggests around 60% of people who stammer have a family member who stammers or used to stammer1

An infographic showing a line drawing of two parents holding an infant child, next to the text '60% of people who stammer have family member who stammers too'.

We also know that:

  • Parents do not cause stammering. It is not your fault. Children do not stammer as a result of being told off. Or because they moved house or a new sibling joined the family.
  • It also has nothing to do with your child learning or speaking more than one language. See Stammering & Bilingual Children for more information.

Causes when stammering starts in adulthood

We know a little bit more about stammering that starts in adulthood. This is sometimes called 'acquired stammering' or 'adult onset stammering'. If an adult starts stammering, it often means their brain has started working in a different way. This might be due to physical changes in the brain caused by a head injury, a stroke, Parkinson's or another illness. Or it could be following a period of intense stress or as a side-effect of medication. Occasionally it's due to none of those things. See Stammers Starting In Adulthood for more information.

Do people stop stammering? 

Around 8% of children — one in every 12 — start to stammer at some point. For most, it will be temporary. Their stammer may stop naturally or following support from speech and language therapy. 

An infographic showing 100 children, with eight of them shaded a different colour, above the text '8% of children will start stammering at some point'.

Some children will continue stammering into adulthood. At the moment, we don't know which children will continue stammering and who will stop. Generally, the longer someone has been stammering, the more likely it is to continue. But there are no certainties. There are no therapies or cures that stop people stammering either. See Is there a Stammering Cure?

But this doesn't have to be something to worry about, for these reasons:

  • Stammering can change over time. People might have periods in their life when they stammer less, as well as others when they stammer a bit more. 
  • Many people find that as they get older they stammer less often.
  • There are things which can help people speak with less struggle, if they wish. There are things which can help people who stammer be confident, skilled communicators. And there are things which can help people feel better about stammering. See Get Help to find out more. 
  • If stammering starts in adulthood, it may change over time depending on what has caused it. See Stammers Starting In Adulthood.

Many people who stammer live happy and successful lives. Did you know that many famous people stammer, or stammered when they were younger? They include Emily Blunt, Ed Sheeran, Bruce Willis, Joe Biden, Rowan Atkinson and Samuel L. Jackson. Marilyn Monroe, Elvis Presley and Charles Darwin stammered too. See Influential People Who Stammer to find out more. 

Is stammering different to stuttering?

No, stammering and stuttering are the same thing. 'Stammering' is what most people in the UK, Ireland and India call it. In North America and Australia most people call it 'stuttering'. There is no difference between them. 

What else do we know?

  • More males than females stammer. Around 75% of people who stammer are boys or men2.
An infographic showing a pie chart, under text saying 'Out of everyone who stammers, 25% are women, 75% are men'.
  • People do not stammer because they are nervous or anxious. It's the possibility of negative reactions from others that can make someone anxious. 
  • People who stammer do not have a certain personality type or level of intelligence. 
  • It has nothing to do with where you are from. People of all ethnicities and from every country can stammer. 

Some conditions are closely related to stammering. Others can happen alongside it. See Cluttering, Stammering & Down's Syndrome, Stammering & Autism and Stammering & Tourette's Syndrome.

Support and more information

Did you find this information helpful? Give us your feedback. We'd love to hear from you.

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Tayo & Bhupinder
A speaker on stage at STAMMAFest 2023

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