Stuttering, also known as stammering or childhood-onset fluency disorder, is a speech condition that disrupts the normal flow and rhythm of speech. People who stutter often experience interruptions in their speech, such as repeating or stretching out sounds, syllables, or words, or pausing at difficult words or sounds. This can make it challenging for them to express themselves, even though they know exactly what they want to say.

While stuttering is relatively common in young children and can be a part of normal speech development, most children eventually outgrow this developmental stuttering. However, for some, stuttering persists into adulthood as a long-term condition, which can impact self-esteem and communication with others.

There are several types of stuttering, each with distinct characteristics:

  • Developmental stuttering (child-onset fluency disorder): This is a neurodevelopmental disorder that arises when brain development diverges from typical patterns. It begins in childhood and is the most common form of stuttering.
  • Persistent stuttering: This type refers to developmental stuttering that continues into adulthood, often requiring ongoing management and support.
  • Acquired stuttering: Unlike developmental stuttering, acquired stuttering occurs due to brain injuries or illnesses that disrupt normal speech patterns.

Various treatments are available to help those who stutter, including speech therapy, the use of electronic devices to enhance speech fluency, and cognitive behavioral therapy, which addresses the mental aspects of stuttering. These interventions aim to improve speech fluency and boost the confidence of individuals struggling with this speech condition.


Stuttering involves involuntary coordination issues among the muscles used for speaking, including those in the face, mouth, throat, chest, and abdomen. To diagnose stuttering, at least one of the following seven key symptoms must be present:

  • Repeating sounds or syllables: Often occurring at the beginning of a word, this involves repeating a sound or syllable until the entire word can be spoken.
  • Prolonged sounds: Getting stuck on a particular sound or syllable and extending it longer than intended.
  • Mid-word pauses: Pausing unexpectedly and for a prolonged time within a word where it is not typically necessary.
  • Blocking: Experiencing frequent silent or vocal pauses (using fillers like “um” or “ah”) that disrupt the flow of speech, often feeling as if something is blocking the words.
  • Word switching: Changing to a different word or phrase mid-sentence to avoid stuttering on a difficult word.
  • Overstressing: Placing excessive stress or tension on parts or all of a word.
  • Repeating single-syllable words: Reiterating a single-sound word, such as “I” or “the.”

Additional characteristics of stuttering include:

  • Spasm overflow: Muscle movements related to stuttering can cause spasms to affect the face, neck, shoulders, and arms.
  • Associated behaviors: Developing habits like unusual blinking, looking away, grimacing, or clenching fists in conjunction with stuttering.
  • Influence of emotions: Symptoms can intensify when feeling tired, excited, anxious, or stressed, and may improve when relaxed.
  • Exemption during specific vocal activities: Stuttering typically does not occur when engaging in activities like speaking to pets, reading aloud, or singing.
  • Impact on mental health: The frustration, embarrassment, and shame associated with stuttering can lead to conditions like anxiety or depression.

Stuttering in children aged 2 to 5 years can be a normal part of speech development and often resolves on its own. However, if stuttering persists for more than six months, occurs with other speech or language issues, intensifies, or continues as the child grows, involves physical tension during speech, affects communication in key settings, or leads to emotional distress and avoidance of speaking, it’s advisable to seek help. You can contact a healthcare professional for a referral or directly schedule an appointment with a speech-language pathologist. This is also recommended if stuttering begins in adulthood.


Experts are still exploring the underlying causes of stuttering, as they remain uncertain about the exact origins of this speech disorder. It is likely that stuttering results from a combination of various factors, including:

  • Developmental stuttering: Children that stutter during the speaking development process. The following are potential reasons of developmental stuttering:
    • Hereditary: The tendency to stutter runs throughout families. It seems that genetic variations inherited from parents to children may be the cause of stuttering.
    • Speech motor control difficulty: Evidence suggests that problems with timing, sensory integration, and motor coordination may be related to speech motor control issues.
  • Stuttering resulting from other causes: Stuttering resulting from causes other than developmental stuttering can impair speech fluency.
    • Neurological stuttering: Repetitive sounds, pauses, or delayed speech can be caused of a brain disease such as stroke, traumatic brain injury, or other brain disorders.
    • Emotional stress: Fluency in speech might be affected when one is experiencing emotional discomfort. Fluency issues can occur in speakers who do not stutter normally when they are anxious or under pressure. Additionally, these circumstances might make stuttering speakers more prone to fluency issues.
    • Psychogenic stuttering: After an emotional trauma, speech problems are rare and distinct from developing stuttering.

Risk factors

The following factors increase the likelihood of stuttering:

  • Childhood developmental condition: Stuttering may be more common in children with developmental disorders such autism, attention-deficit/hyperactivity disorder, or developmental delays. This also applies to children who have other speech issues.
  • Family history: Having a tendency to stutter runs throughout families.
  • Gender: Compared to females, males stutter far more frequently.
  • Stress: Family tension as well as other forms of strain or stress may worsen pre-existing stuttering.
  • Structural difference of brain: Brain abnormalities in specific regions are more common in stutterers. Usually, these are the regions that regulate the muscles used for speech or motor coordination.