What is the author's style in Death at La Fenice by Donna Leon?

In Death at La Fenice, language is informed by the relationships between people. Though the novel is in English, the characters are usually speaking Italian, and in Italian, there are two forms of address: formal and informal. The narrator comments on when the characters use formal or informal modes of address with each other. When Brett breaks the ice with the detective, admitting to her relationship with Flavia, she moves from the formal to the informal mode of speech. She is becoming friendlier and closer to Brunetti.