Lee's language is respectful in describing the Cunninghams and this reflects an overall respect for those who suffered through the Great Depression.
We learn about the Cunninghams early in the book when Scout has a run-in with Walter at school. In trying to describe the Cunninghams' economic status compared to their own, Atticus explains to Scout and Jem:
"The Cunninghams are country folks, farmers, and the crash hit them the hardest" (Ch.2).
We learn that the Cunninghams pay for services with food when they are able to, as they have so little money. Lee describes them as dignified people who work for what they earn and pay for what they take. They do not accept charity or hand-outs. This relates to the Great Depression because farmers and country folk were hit very hard, but they did not expect hand-outs either. They often had large pieces of land to take care of and if no one had the money to buy their products, they could not easily go and make money elsewhere. They resorted to living off of their land or going hungry and making ends meet or trading in whatever ways they could to get by, just like the Cunnighams. Many farms were in rural and poor areas already, so the economic downturn meant that the farmers and small towns suffered even more.
Atticus and Jem both treat the Cunninghams with respect and seem to understand that the circumstance is not the same as the person.