Stuttering

v. falter or pause frequently while speaking, stammer

Stuttering, also known as stammering in the United Kingdom, is a speech disorder in which the flow of speech is disrupted by involuntary repetitions and prolongations of sounds, syllables, words or phrases, and involuntary silent pauses or blocks in which the stutterer is unable to produce sounds. 'Verbal non-fluency' is the accepted umbrella term for such speech impediments. 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 stutterers as blocks, and the prolongation of certain sounds, usually vowels. Much of what constitutes "stuttering" cannot be noted by the listener; this includes such things as sound and word fears, situational fears, anxiety, tension, self-pity, stress, shame, and a feeling of "loss of control" during speech. The emotional state of the individual who stutters in response to the stuttering often constitutes the most difficult aspect of the disorder. The term "stuttering", as popularly used, covers a wide spectrum of severity: it may encompass individuals with barely perceptible impediments, for whom the disorder is largely cosmetic, as well as others with extremely severe symptoms, for whom the problem can effectively prevent most oral communication.
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Stuttering is a speech problem characterized by repetitions, pauses, or drawn out syllables, words, and phrases. [more]Stuttering - Community and Resources

Adjective
1. unable to speak freely and easily
(synonym) stammering(a), stuttering(a)
(similar) inarticulate, unarticulate

Noun
1. a speech disorder involving hesitations and involuntary repetitions of certain sounds
(synonym) stammer
(hypernym) speech disorder, speech defect, defect of speech
(derivation) bumble, stammer, falter
Verb
1. speak haltingly; "The speaker faltered when he saw his opponent enter the room"
(synonym) bumble, stammer, falter
(hypernym) talk, speak, utter, mouth, verbalize, verbalise
(derivation) stammerer, stutterer

(p. pr. & vb. n.)
of Stutter
  

(n.)
The act of one who stutters; -- restricted by some physiologists to defective speech due to inability to form the proper sounds, the breathing being normal, as distinguished from stammering.
  

(a.)
Apt to stutter; hesitating; stammering.