Fluent speech is smooth, forward-moving, unhesitant and effortless speech. A "dysfluency" is any break in fluent speech. Everyone has dysfluencies from time to time. "Stuttering" is speech that has more dysfluencies than is considered average.

Everyone has dysfluencies in their speech. The average person will have between 7-10% of their speech dysfluent. These dysfluencies are usually word or phrase repetitions, fillers (um, ah) or interjections. When a speaker experiences dysfluencies at a rate greater than 10% they may be stuttering. Stuttering is often accompanied by tension and anxiety. The types of dysfluencies in stuttering may also be different. Sound or syllable repetitions, silent "blocks", and prolongations (unnatural stretching out of a sound) and facial grimaces or tics can be present.

There are many different kinds of dysfluencies. Dysfluencies heard in the speech of normal speakers include fillers (um, ah), hesitations, whole word and phrase repetitions, and revisions. Dysfluencies that are more characteristic of stuttering include sound or syllable repetition, prolongations (unnatural stretching out of sounds),and blocks (sound gets stuck and can't come out). Stuttering can be differentiated from normal dysfluencies by the type, frequency and duration of dysfluency. A percentage of dysfluency can be determined by counting the number of dysfluencies in a 100 words. The average speaker has upto 7% dysfluencies of the types described above. They are usually rapid and don't slow speech down. Stuttering occurs at frequencies of 10% and up and can last from a half second up to 30 seconds, and is accompanied by tension.

Many children go through a period of normal nonfluency between the ages of 2 and 5 years. The frequency of dysfluency can be 10%, sometimes greater. The dysfluencies are usually whole word or phrase repetitions and interjections. The word is repeated just once or twice and is repeated easily. The child does not demonstrate any tension in their speech and is often unaware of their difficulty. It has been suggested that the cause of this nonfluency may be a combination of increases in language development, development of speech motor control, environmental stresses that can occur in typical busy families. Some children "outgrow" these dysfluencies, others do not.

There have been many theories about the cause of stuttering and many misconceptions exist. Currently, it is believed that a number factors play a role in the development and maintenance of stuttering. These factors can be grouped and classified as constitutional, environmental and communication factors. There is some evidence that stuttering is genetic; it does run in some families. There is also evidence that stuttering is due to a disorder in the timing of movements of speech muscles, a defect in auditory feedback, and a lack of cerebral dominance for language functions. Researchers in San Diego reported results of a study using positron emission tomography scanning (PET scan) that supports all three of the above causes. In normal, right-handed individuals, language functions are localized to the left side of the brain. PET scanning allows one to look at brain activation during different activities. Stutterers showed a shift in brain activation from the left to the right side of the brain, suggesting that they process language differently. This right-side activation occurred when stutterers were stuttering and speaking fluently.

There are many myths about stuttering. Here are some facts:

Stuttering occurs more often in males than females, about 3:1.
The incidence of stuttering is reported to be between 5-10%.
Stuttering is not a symptom of emotional or mental problems. Stuttering may be a source of stress and cause emotional difficulties.
Stutterers are not less intelligent than normal speakers; they are of normal intelligence.
Stuttering is not learned by imitating others who stutter.

There are as many different treatment approaches as there are theories about the cause of stuttering. Therapy is different depending on the age of the stutterer. There is no "cure" for stuttering. Stuttering can be prevented in preschoolers and young borderline stutterers through environmental manipulation and parent counselling. Advanced stutters learn skills and strategies to manage their stuttering.

Environmental manipulation involves identifying variables in the child's environment that are increasing dysfluencies and then reducing or eliminating them. Some variables include: competition for talking time, listener loss, interruptions, pressure to speak or perform, too much or too little structure, sibling rivalry, fast-paced, busy environment, high level of excitement.

Treatment approaches generally fall into 2 different camps: "speak more fluently" or "stutter more easily". An integration of these 2 approaches is ideal for many individuals. The "speak more fluently" approach focuses on learning "targets" or fluency-enhancing skills (e.g., easy onsets, light contacts, blending). The "stutter more easily" approach helps the stutter to reduce tension and modify his/her stuttering so that it doesn't interfere with his/her ability to communicate.

Most intensive fluency programs will help a stutter to feel more confident and to speak more fluently. Unfortunately, the gains made in therapy are not always maintained when therapy is finished. The stutterer must be motivated and dedicated to continue to practise their techniques as often as they need to in order to maintain their fluency.

When speaking with an individual who stutters it is helpful to focus on what they say rather than how. Modifying your own speaking rate to one that is slightly slower and inserting pauses into your speech sets the pace. Be relaxed and attentive. Don't look away if they get stuck; on the other hand don't stare at them intently. Don't interrupt or finish their sentences. Advice such as "slow down", "relax", "take a breath" is NOT helpful. It often increases tension and thus stuttering.