What is the author's style in The White Hotel by D. M. Thomas?

As with point of view, the language of the novel changes depending on the chapter. The prologue is fairly straightforward. The language of each letter depends on who is writing to whom. For instance, Freud is friendly and quite casual in his letters to Ferenczi, but uses a formal, technical voice when discussing Lisa's writings with Herr Kuhn, who Freud hopes will publish his work and Lisa's writings. Other letters throughout the book share similar characteristics.