What is the author's style in Whitney, My Love by Judith McNaught?

he novel contains exposition that is simple and reflects the time in which the novel was written. However, the novel also contains dialogue that is stiff and grammatically correct, reflecting the time period in which the novel is set. There is little slang in the novel, but there are words in foreign languages, specifically French, reflecting the fact that one of the settings of the novel is Paris, France. These phrases are often spoken by characters living in France and are easily explained within the dialogue in which they appear; moreover, most educated English of that era spoke French fluently.