Signs have only one meaning. Verbal statements encourage verbal responses. Silent signals encourage silent responses. Teacher focuses on misbehaving students during disciplinary intervention.
Teacher focuses on teaching while signaling to the misbehaving students.
Voice inflection and body language influence the teacher's message. Teacher's hand signals send an impersonal, non-threatening message. Verbal messages require time to think and deliver. Signs are sent instantly and take minimal time to learn. Words interrupt and disrupt learning.