Why does Chopin choose to have Desiree say that Armand "can hear the crying from La Blanche's cabin?"

Chopin's story "Desiree's Baby" is filled with subtlety and ambiguities. The seemingly unimportant detail that Desiree divulges about Armand's location suggests an interesting alternative to the standard interpretation of the story. The most obvious reason that Desiree exclaims "Ah!" when she looks back and forth between her child and La Blanche's child, who is of mixed race, is that she finally recognizes African features in her own child. However, another interpretation is that she recognizes...

Chopin's story "Desiree's Baby" is filled with subtlety and ambiguities. The seemingly unimportant detail that Desiree divulges about Armand's location suggests an interesting alternative to the standard interpretation of the story. The most obvious reason that Desiree exclaims "Ah!" when she looks back and forth between her child and La Blanche's child, who is of mixed race, is that she finally recognizes African features in her own child. However, another interpretation is that she recognizes Armand's likeness in both the quadroon boy and her own son. 

Chopin suggests at several points in the story that Armand treats his slaves brutally. Desiree's mother considers how Armand's "rule was a strict one, too, and under it his negroes had forgotten how to be gay." After the baby's birth, Desiree is thrilled that Armand has stopped punishing the slaves. However, when the baby is about three months old, Armand rejects Desiree and the child, and "the very spirit of Satan seemed suddenly to take hold of him in his dealings with the slaves." Desiree is nothing if not naive; that she blithely speaks of Armand being at La Blanche's cabin shows her innocence as much as it suggests Armand's guilt. The reader has reason to wonder, if Desiree doesn't, what possible reason the owner of a large plantation would have to personally visit the cabin of a female slave. That he is there during the weeks of Desiree's recovery from the birth, when she would not be able to give him the attention he was used to, is also telling.

Given Armand's oppression of his slaves, it is certainly possible and even likely that he uses La Blanche and possibly the other women slaves as concubines and that the quadroon boy is one of his illegitimate offspring. Desiree notes that "Armand is the proudest father in the parish" now that he has "a boy  to bear his name." Armand possibly already has one or more sons, but none that can "bear his name" until Desiree's baby.

The reference to Armand being at La Blanche's cabin helps Chopin characterize Desiree as naive and trusting and Armand as despicable, and it also provides ambiguity that allows an alternate interpretation of the way the plot develops.