Stuttering Iceberg: Meaning, Origin, Examples and Worksheet

Quick answer: The stuttering iceberg is a model showing that the speech behaviors listeners can hear, such as repetitions, prolongations, and blocks, are only a small visible part of stuttering. Below the waterline sit fear, shame, avoidance, and word substitution. The analogy is credited to psychologist and stuttering researcher Joseph Sheehan, who introduced it around 1970. The "ninety percent" often attached to it is a metaphor, not a measured statistic.

If you or someone you love stutters, the iceberg explains why fluent-sounding speech is not always the same as comfortable speech. At the World Stop Stuttering Association, we work with people who want to stop stuttering, and the iceberg is where almost every conversation starts. It shows why our online stuttering therapy does not stop at speech techniques, and why the neuroscience method also works on fear, avoidance, and identity, the layers that sit beneath the surface.

In this guide:

• The iceberg analogy explained

• Who created it, and what the "90 percent" really means

• What sits above and below the waterline

• A day below the waterline: real examples

• Why the hidden layers matter for therapy

• The iceberg and covert stuttering

• The iceberg in children and teens

• A step-by-step stuttering iceberg worksheet, with an example

• How the iceberg shrinks, and how to support someone who stutters

• Frequently asked questions

What Is the Stuttering Iceberg?

The stuttering iceberg is a picture with a waterline across the middle. About one part of an iceberg shows above the water, and the much larger mass stays hidden beneath it. Stuttering works the same way.

• Above the surface: the observable behaviors, meaning what a listener can see and hear.

• Below the surface: the emotions, thoughts, avoidance habits, and beliefs that the speaker lives with but the listener cannot detect.

The model matters because most people, including many teachers, coworkers, and even some clinicians, judge stuttering only by what they hear. A person who stutters rarely or mildly in public may still be carrying an enormous hidden load. A person who stutters openly may feel more at ease than someone who sounds smooth but is constantly managing and hiding. Sound alone cannot tell you where someone is on the iceberg.

Who Created the Iceberg Analogy of Stuttering?

Joseph Sheehan, a psychologist and stuttering researcher, is credited with popularizing the iceberg analogy around 1970. Sheehan believed that stuttering was driven in large part by conflict: the urge to speak colliding with the urge to hold back out of fear. That idea, often called approach-avoidance conflict, is why the hidden emotional layers sit at the heart of his model rather than at its edges.

The analogy stuck because it explains in one image what clinical definitions struggle to capture. Today it is used by speech-language pathologists, support groups, and people who stutter worldwide.

In the UK and elsewhere the model is usually called the stammering iceberg. The idea is identical; see stammer vs stutter for the terminology.

Is the 90 percent figure real? No. The number comes from how real icebergs float, with most of their mass underwater. In the stuttering iceberg it is a metaphor for "much more is hidden than seen." Nobody has measured a precise percentage, and it will differ for every person.

Above the Waterline: What Listeners See and Hear

The tip of the iceberg is made of overt behaviors. These are covered in detail in our guide to the core behaviors of stuttering:

• Repetitions: sounds, syllables, or words repeated, like "b-b-b-book."

• Prolongations: sounds stretched out, like "ssssnake."

• Blocks: the mouth is in position, but no sound comes out.

On top of these sit the secondary behaviors of stuttering: eye blinks, jaw or lip tension, head jerks, foot tapping, and filler words used to push through a hard moment. These are learned reactions to stuttering, and they are still on the visible side of the waterline.

This is the part that teachers notice in classrooms, coworkers hear in meetings, and strangers react to in everyday life. It is real, but it is the smallest part of the experience.

Below the Waterline: What Listeners Never See

The hidden mass has four main layers.

1. Emotions. Fear, embarrassment, frustration, anger, helplessness, and sadness. The emotional effects of stuttering can build for years, and the research literature consistently finds higher rates of social anxiety in adults who stutter than in the general population. See also stuttering and depression.

2. Thoughts and mental effort. Constant word scanning, always reading three or four words ahead to spot sounds that might trigger a block. Rehearsing sentences before saying them. Replaying conversations afterward and judging how they went.

3. Avoidance behaviors. Switching words at the last second, pretending to forget what you wanted to say, skipping phone calls (see phone call anxiety), letting someone else order, or staying quiet in a group when you have something worth saying. Choosing words to dodge a sound is a form of circumlocution.

4. Identity-level beliefs. "I am not someone who speaks up." "People will think I am stupid." "I could never do a job that involves talking." These beliefs form slowly through years of difficult moments. They become so familiar that they feel like facts, not opinions.

A Day Below the Waterline: Real Examples

Most people who do not stutter have no idea how much mental energy goes into managing it every day.

Word substitution. You want to say "I would like the chicken parmesan," but you sense a block coming on "chicken." So you say, "I will have the pasta." The listener never knows a substitution happened. You do, and that small surrender chips away at confidence. Repeat it dozens of times a day for years and the toll becomes clear.

Situation avoidance. Turning down a promotion because it involves presentations. Putting off a doctor's call for weeks. Walking into a coffee shop, seeing a line, and walking back out. These look like preferences to everyone else. To the person who stutters, they feel like defeats. Our guides on stuttering at work and the fear of being judged when speaking go deeper on these moments.

Emotional exhaustion. Monitoring your own speech, scanning ahead, rephrasing on the fly, and performing fluency for the people around you is a heavy cognitive load. Many people who stutter feel physically drained after social events, not because the socializing was hard but because the background speech management used so much mental bandwidth.

Shame and identity. At the very bottom, many people come to believe that something is wrong with them as a person, not just their speech. This is the deepest layer, and it often takes the longest to address. See how stuttering affects confidence and how to rebuild it and how to let go of shame when speaking.

Why the Hidden Layers Matter for Therapy

Therapy that targets only the tip can leave most of the experience untouched. Someone can learn smooth-speech techniques and still avoid speaking situations because the fear beneath was never addressed. This is why many clinicians now measure more than speech behavior.

• The OASES (Overall Assessment of the Speaker's Experience of Stuttering) looks at how stuttering affects a person's feelings, thoughts, communication, and quality of life, not just how often they stutter.

• The World Health Organization's ICF framework looks at health in terms of participation in daily life, not only body function, which is why many clinicians assess more than speech behavior.

• Many programs combine fluency shaping (changing how speech is produced) with stuttering modification (changing how you react to and move through stuttering). The differences are explained in fluency shaping vs stuttering modification.

The iceberg suggests a practical rule: effective support works on all three zones, the tip (speech behaviors), the middle (avoidance and anxiety), and the base (shame and identity). Results vary from person to person, and working with a licensed speech-language pathologist alongside any program is a good idea. If you are looking for one, read how to find a speech therapist.

The Stuttering Iceberg and Covert Stuttering

The iceberg fits covert stuttering especially well. Covert stutterers hide, avoid, or swap words so effectively that listeners rarely notice anything. In their case almost the whole experience sits below the waterline. A smooth-sounding speaker can be exhausted, anxious, and quietly limiting their life, which is why "you do not even stutter" is rarely comforting to hear.

The Iceberg in Children and Teens

Young children often stutter without much awareness, so their iceberg is mostly tip. That can change as they grow. Teasing, being cut off, or noticing that others react can start building the hidden layers, sometimes as early as the school years. Our guides to toddler stuttering and stuttering and bullying explain the early signs and how parents can respond. Early support protects not just fluency but the child's confidence as a speaker.

Stuttering Iceberg Worksheet: Map Your Own Experience

A stuttering iceberg worksheet is a simple self-awareness exercise. It takes about 15 minutes.

Step 1: Draw the iceberg. On a blank page, draw an iceberg and a horizontal waterline across it.

Step 2: Fill in the top. Above the line, write what others can see and hear. Be specific. Not "I block," but "I block hard on words starting with B and P, especially with authority figures."

Step 3: Fill in the bottom. Below the line, write everything internal: feelings, fears, avoided situations, swapped words, things you did not say, rehearsal habits, and beliefs about yourself as a speaker and as a person. This half is almost always longer, and that is the point.

Step 4: Rate each item. Give each hidden item a score from 1 (barely matters) to 10 (affects my life most).

Step 5: Choose one thing to work on. Pick one item from the bottom with a 5 or 6, not the scariest one, and write one small action for this week.

Example of a filled-in iceberg

• Above the waterline: blocks on B and P words; jaw tension when speaking to my manager.

• Below the waterline: fear of meetings; swapping "chicken" for "pasta" when ordering; avoiding phone calls; rehearsing sentences in advance; feeling drained after social events; the belief that "people will think I am not capable."

• First action: once this week, order the item I actually want without switching words.

Reflection prompts

• What do I avoid that I would do if I did not stutter?

• Which words or sounds do I swap most often?

• What do I wish people understood about my speech?

• Which belief about myself would I most like to change?

To make the worksheet more concrete, you can rate your experience with the stuttering self-rating scale, and explore your triggers in triggers for stuttering. If anxiety fills the lower half of your drawing, our guide to communication anxiety can help.

Once your iceberg is on paper, it stops being a vague, overwhelming problem and becomes a list of specific challenges you can work on one at a time. Many speech therapists use this worksheet as a starting point for the same reason. You do not need a therapist to start, though. Grab a piece of paper tonight and be honest about what goes below the line.

How the Stuttering Iceberg Changes With the Right Support

The iceberg is not fixed. It can shrink, and not only the visible part.

The tip shrinks with practice. When someone practices techniques daily (see how to practice stuttering therapy techniques at home) and uses them in real conversations, blocks often get shorter, repetitions less tense, and prolongations easier.

The middle thins with exposure. Deliberately entering situations you used to avoid, such as group practice, phone call challenges, or ordering your own food without switching words, gradually reduces avoidance. A structured way to do this is a fear hierarchy, where you rank situations from least to most frightening and climb one step at a time. Another approach is paradoxical intention, where you practice stuttering openly on purpose to remove its power. Each small success teaches the brain that the situation is manageable.

The base softens with connection and reframing. Hearing from people who have been through it, separating identity from speech pattern, and replacing the story "I am a stutterer and that is all I will ever be" with "I am a person who happens to stutter, and I am changing my relationship with speech." Reading famous people who stuttered and how they overcame it can make that shift feel more possible.

This does not happen overnight, and progress looks different for everyone. But daily practice, accountability, expert guidance, and a community that understands make a real difference across every layer. You cannot melt an iceberg by chipping only at the top.

How to Support Someone Whose Iceberg You Cannot See

If someone in your life stutters, assume there is more beneath the surface than you can hear.

• Give them time to finish. Do not complete their sentences or tell them to relax.

• Keep natural eye contact and keep listening to the message, not the stutter.

• Do not praise "fluent" speech in a way that implies stuttering is failure.

• Ask what helps rather than guessing.

For partners, see how to support your partner who stutters. If you are the one who stutters and want to open up at work, read how to talk to your employer about your stutter.

Common Misreadings of the Iceberg

• "It means stuttering is mostly in your head." No. Stuttering has real neurological and motor components. The iceberg says the experience is bigger than the sound, not that the sound is imaginary.

• "It means fluency does not matter." No. Many people want smoother speech, and that is a valid goal. The iceberg says fluency alone is not the whole goal.

• "The bottom is always worse than the top." The proportions differ for everyone. Some people carry little below the waterline, and that is just as valid.

• "The 90 percent is a statistic." It is a metaphor.

Frequently Asked Questions

What is the stuttering iceberg?

A model showing that the visible speech behaviors of stuttering are only a small part of the full experience. Below the surface sit fear, avoidance, shame, word substitution, situation dodging, and deep identity beliefs.

Who created the stuttering iceberg analogy?

Joseph Sheehan, a psychologist and stuttering researcher, popularized it around 1970. It is now one of the most widely used frameworks in stuttering therapy.

What is above the waterline in the stuttering iceberg?

Overt behaviors such as repetitions, prolongations, blocks, and visible tension.

What is below the waterline?

Emotions, word scanning, avoidance, word and situation switching, mental fatigue, and identity-level beliefs.

How do you use a stuttering iceberg worksheet?

Draw an iceberg with a waterline. List observable behaviors above it, and internal experiences below it. Rate each item and pick one small thing to work on this week.

Can the stuttering iceberg shrink?

For many people, yes. Consistent practice, real-world exposure, community support, and mindset work can reduce both the visible and hidden parts over time.

Is the 90 percent figure a real statistic?

No. It is a metaphor taken from how real icebergs float.

Does the iceberg model apply to covert stuttering?

Yes, especially well. In covert stuttering, most of the experience sits below the waterline.

Is the stuttering iceberg the same as the stammering iceberg?

Yes. "Stammering" is the more common term in the UK and elsewhere. The model is identical.

Does everyone who stutters have a big hidden iceberg?

No. The size of the hidden part varies a lot between people, and it can change over time.

Final Thoughts

The stuttering iceberg reminds us that speech is only the surface of a much larger human experience. The people who benefit most are those who stop asking only "how do I sound?" and start asking "what am I carrying, and what do I want to change?" Map your iceberg, pick one small step, and keep going. If you want company and guidance on the way, the WSSA team is here to help you build a plan for confident, fluent speech.