In A Raisin in the Sun, the tone is somber, depressing yet realistic. The Younger family lives in a segregated Chicago neighborhood. The apartment is worn from too many people living in it:
The family's inadequate living situation is conveyed through the fact that they share a bathroom with other tenants in their apartment house and through the fact that Travis must sleep on the sofa in the living room.
At times, the tone comes across as sarcastic and critical because of the characters' dialogue. Walter and Beneatha argue constantly. Walter believes Beneatha's dream of becoming a doctor is not realistic. He criticizes her dream, telling her to become a nurse, which is a more realistic dream.
Likewise, Beneatha criticizes Walter's dream of becoming a business man. The tone is quite sarcastic and critical and realistic during most of the play. There is definitely a lack of respect from Walter and Beneatha for one another.
The tone is quite serious and depressing. The Younger family has such a hard time trying to make it in life. Walter is a chauffeur, and he resents his job. Ruth and Mama do housework and laundry for other families. The atmosphere is gloomy, almost without hope, except for the fact that the father's insurance check is expected in the mail.
Ultimately, the tone changes as the future becomes brighter for the Younger family. Mama buys a house and the characters create a tone of hope. Although the tone is still realistic, knowing to expect controversy by moving into an all white neighborhood, there is an excitement in the Younger family's voices as they move into their new home.