Stream-of-consciousness writing is usually regarded as a special form of interior monologue and is characterized by associative leaps in thought and lack of punctuation.
His imaginative use of point of view, interior monologue and possibly unreliable narrators in his own novels and tales brought a new depth and interest to narrative fiction.
Analogous with music (music being taken as the origin of language), interior monologue had an affinity with a more primitive and thus more original language.