Animal Behavior (1989)
Serious college music professor falls in love with kooky female animal behavior researcher who is committed to proving that chimpanzees can communicate with humans through sign language. She succeeds when her chimpanzee communicates with an emotionally disturbed child who is refusing to speak.
Animal Action

The chimp is depicted as a loving and intelligent pet capable of learning to communicate with humans. Other animals seen are a caged monkey briefly screeching in a lab and a dog sitting on a porch as atmosphere.