LitCharts assigns a color and icon to each theme in The Color Purple, which you can use to track the themes throughout the work.
God and Spirituality
Race and Racism
Men, Women, and Gender Roles
Violence and Suffering
Self-Discovery
Summary
Analysis
Six months later, Squeak begins singing around the house. Her voice is strange and high-pitched, not formally trained, but everyone, Celie includes, grows to love it. Harpo is surprised by Squeak's singing, but he lets Squeak continue to sing. One of her songs talks about her "yellow" skin. It is also revealed that Sofia is now in charge of the mayor's children; Squeak's efforts, though traumatizing to her, have been successful, and have earned Sofia a position as maid and servant to the mayor's family.
As above, Squeak's efforts at singing, a form of artistic expression, mirror Celie's efforts, later in the novel, at making parts and starting her own business. Both Celie and Squeak realize that they have more to offer the world than simply their services as wives, mothers, and housekeepers. This realization is an important part of the novel's theme of self-discovery.