Childhood fluency disorder is a communication disorder characterized by a disturbance in the flow and timing of speech that is inappropriate for an individual’s age. Also referred to as stuttering, this condition includes the repetition or prolongation of speech sounds, hesitations before and during speaking, long pauses in speech, effortful speech, and/or monosyllabic whole-word repetitions. This condition is typically accompanied by anxiety about speaking and can place limitations on how comfortable a child feels participating in social or academic environments.

Source: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition