Answer:
Controlling function.
Explanation:
One of the ways how nonverbal messages can be conveyed is gestures. People often help themselves to support what they have to say with gesticulation or use it as the only means of delivering the message. Usage of body language and facial expressions is the original form of communication between humans, because language has developed much later. Thus it often comes more naturally and quicker.
Here, Alicia uses her body language in the form of gesture instead of just saying stop. In this way she exercise control, but also does not want to appear rude. Curiously, just usage of the word 'stop' in many cultures would be considered extreme and inappropriate. At the same time, more vigorous hand gesture considered very normal in southern cultures as Italian, while they would seem very inappropriate in the Northern culture like Finnish.