The fact that berta uses her lips instead of her finger to point at an object across the room illustrates that communication is

Symbolic

Explanation:

Symbolic communication is defined communication that takes place through symbols ,gestures, body language and facial expression without speaking verbally. This can change the presupposed expectation of any situation.It can also persist several meaning in respect to one symbolic expression.

Example of symbolic communication is the symbolic language developed for modern technologies language for exchanging message.

According to the situation in question, Berta is using symbolic language for indicating the objects through her lips  rather than using the fingers .This changes the expected priori meaning of the event.

answer; positive reinforcement;