Mrs. Bennet scolds Kitty for her persistent coughing, which, as well as being rather annoying, plays havoc with Mrs. Bennet's already fragile nervous system. That Mrs. Bennet should show such little concern for her daughter's health shouldn't surprise us too much. But as this was a time when persistent coughing was often a sign of tuberculosis, which was a virtual death sentence in most cases, one might have thought that a little more sympathy was in order.

Or perhaps Mrs. Bennet, in a rare flash of insight, has worked out that Kitty isn't really ill at all—that her coughs are expressions of embarrassment, or possibly disapproval at her mother's breathtaking hypocrisy in her negative evaluation of Mrs. Long. It is notable that Kitty only seems to start coughing when Mrs. Bennet gives her considered opinion that Mrs. Long is a selfish, hypocritical woman. Then, in the very next breath, she says that she has no opinion of her, despite having just given everyone a very forthright opinion of what she thinks of this woman.

One gets the impression that, by coughing, Kitty is subtly drawing attention to the shameless hypocrisy of her mother in criticizing someone else for having the exact same character flaws as herself.