I am mulling the idea of writing a novel in which the only dialogue is internal. Has anyone yet published such a novel?
I define "dialogue" here as any kind of speech addressed by a fictional person to a fictional person. This includes monologue insofar as a person who speaks to themselves, either out loud or internally, is still speaking to a person even if they are not addressing somebody else. In the sense that writing is a form of "speech", an epistolary novel comprising a collection of personal letters also contains dialogue. Excluded from the definition are first-person narrative when the addressee is the reader, because the reader is not fictional; and most stream of consciousness writing, unless it is sufficiently formally similar to literal speech to be considered "addressed".
On this definition, I am not aware of any novels that are completely free of dialogue. But are there some in which the only dialogue is internal? I would like to know so that I can study the authors' techniques and use them, perhaps adapted, in my own writing.
(The first and last sentences above were added following advice received by @Cloudchaser.)