
The disorder is also variable, which means that in certain situations, such as talking on the telephone or in a large group, the stuttering might be more severe or less, depending on whether or not the person who stutters is self-conscious about their stuttering. Neither acute nor chronic stress, however, itself creates any predisposition to stuttering. Acute nervousness and stress are not thought to cause stuttering, but they can trigger stuttering in people who have the speech disorder, and living with a stigmatized disability can result in anxiety and high allostatic stress load (chronic nervousness and stress) that reduce the amount of acute stress necessary to trigger stuttering in any given person who stutters, worsening the situation in the manner of a positive feedback system the name 'stuttered speech syndrome' has been proposed for this condition. Stuttering is generally not a problem with the physical production of speech sounds or putting thoughts into words.

Stuttering is sometimes popularly seen as a symptom of anxiety, but there is no direct correlation in that direction. This may include fears of having to enunciate specific vowels or consonants, fears of being caught stuttering in social situations, self-imposed isolation, anxiety, stress, shame, low self-esteem, being a possible target of bullying (especially in children), having to use word substitution and rearrange words in a sentence to hide stuttering, or a feeling of "loss of control" during speech. The impact of stuttering on a person's functioning and emotional state can be severe. Almost 70 million people worldwide stutter, about 1% of the world's population. The term "stuttering" covers a wide range of severity, from barely perceptible impediments that are largely cosmetic to severe symptoms that effectively prevent oral communication. For many people who stutter, repetition is the main concern. According to Watkins et al., stuttering is a disorder of "selection, initiation, and execution of motor sequences necessary for fluent speech production". The term stuttering is most commonly associated with involuntary sound repetition, but it also encompasses the abnormal hesitation or pausing before speech, referred to by people who stutter as blocks, and the prolongation of certain sounds, usually vowels or semivowels.

Stuttering, also known as stammering, is a speech disorder in which the flow of speech is disrupted by involuntary repetitions and prolongations of sounds, syllables, words, or phrases as well as involuntary silent pauses or blocks in which the person who stutters is unable to produce sounds. Usually resolves by late childhood 20% of cases last into adulthood Shame, bullying, social anxiety, fear of public speaking Involuntary sound repetition and disruption or blocking of speech Stuttering ( / ˈ s t ʌ t ər ɪ ŋ/), stammering ( / ˈ s t æ m ər ɪ ŋ/.
