Stuttering is a neuromuscular speech disorder. It affects the coordinated movements of the organs and muscles used to produce speech (vocal cords, tongue, lips, jaws, respiratory muscles, etc.). Many people are born with a weaker speech system (genetic predisposition). Individual and environmental factors can significantly impact a weaker speech system, such as fatigue, stress, emotions, attitudes, time constraints, etc. About 5% of children stutter at one moment or another in early childhood, while persisting stuttering problems affect only 1% of the population.
Stuttering occurs when the flow of speech is disrupted, also called speech disfluency. Sound, syllable, word or phrase repetitions, sound prolongations, and blockage of speech are a few examples of what characterizes speech disfluency. These speech disruptions may also be accompanied by other behaviours, such as eye blinks, head movements, restless feet or hands. These are referred to as associated movements. Speech fluency, or fluid speech, corresponds to undisrupted flow of speech.
Stuttering most often occurs in early childhood, between 2 and 5 years of age. Many preschool-aged children may experience a developmental stuttering problem. In other words, it is a temporary problem from which children recover on their own, usually one year after its onset.