Knowledge of the rules that govern how we encode and decode linguistic utterances can be thought of as being organized into three components: the semantic-syntactic knowledge base, the phonological knowledge base, and the phonetic knowledge base.
There are many stuttering problems for people who stutter. People with an established stutter are aware of the negative effect of repetitions, prolongations, hesitations and blocks on their speech. Their stutter (stammer) may be accompanied by facial tics and uncontrolled body movements. Stuttering can lead to the avoidance of certain activities and to social isolation.