Sofia | Squeak

Exposition: Sofia doesn't care for Squeak when they first meet at Harpo's bar.
Rising Action: Squeak gets jealous and defensive when she sees Harpo and Sofia dancing, talking, laughing, and having a good time together. Sofia is simply annoyed that this little thing keeps bugging her.
Climax: Sofia's tolerance quickly wears thin and she knocks Squeak out.
Solution: When Sofia comes to visit after she got out of jail, Squeak stands up for herself at the table, telling Harpo that her name is Mary Agnes, not squeak. Sofia starts to respect Squeak more because of this.

Squeak finally speaks up, telling Harpo that she wants to sing, but Harpo quickly shoots the idea down. Squeak used the strength that she got from Celie, who got it from Sofia, to stick up for herself and leave to Memphis with Celie and Shug without Harpo's consent.

"Listen Squeak, say Harpo. You can't go to Memphis. That's all there is to it. Mary Agnes, say Squeak. Squeak, Mary Agnes, what difference do it make? It make a lot, say Squeak (203)."

Much like the situation with Celie, Sofia and Squeak's relationship helped Squeak become a stronger woman.  When the two first met, Squeak was jealous and insecure. By the end of the book, Squeak had mustered up the courage to face Harpo and go off to Memphis with Celie and Shug without having to ask him. Seeing someone as weak as Squeak take a stand like that made Albert and Harpo think twice about controlling the women they were married to. This relationship was just to reinforce the idea that as long as women were emotionally stronger, they wouldn't be dominated by men.