Dysfluent speech is referred to by either term, "stuttering" in American English or "stammering" in British English. They refer to a disruption in the speech's flow or fluency. Stuttering is a disease characterized by pauses, repetitions, prolongations, hesitations, and sometimes involuntary bodily movements that impair verbal fluency. Preschoolers are the ones most likely to stutter or stammer. It has been estimated by researchers that 5–10% of kids stutter at some point. Compared to girls, boys are more likely to stammer.