Difficulty in production of fluent speech, as in stuttering.

The “smoothness” of speech, dysfluent speech may be referred to as stuttering (see below). This is measured by sound/word/phrase repetitions, sound elongations, interruption of airflow and other measures.

Any type of speech which is marked with repetitions, prolongation, and hesitations; an interruption in the flow of speech sounds

A disturbance of language fluency.