Stuttering is a fluency disorder. It is also known as ‘stammering’ in some parts of the world. Stuttering is characterized by disruptions in the production of speech sound, which may be in the form of repetitions, prolongations or blocks. One or any combination of these behaviours may be observed consistently or variably. The frequency, duration, type, and severity of disfluencies vary greatly from child to child and from situation to situation with the symptoms appearing between the ages of 2.5 to 4 years. It is also possible for stuttering to start during primary school. About 5% of children display stuttering behaviours and stuttering is more commonly observed in males than females. Preschoolers may have little or no awareness of their fluency difficulties, especially so when they first start to display stuttering behaviours. However, most people who stutter become increasingly aware of their fluency difficulties and the responses they receive when they do not speak fluently.
The exact cause of stuttering is currently unknown. Recent studies have suggested that genetics plays a role in the development of the disorder and that abnormalities in speech motor control, such as timing and sensory and motor coordination, are implicated.