The 20th century writers understood it was impossible to reproduce the complexity of the human mind using traditional techniques and looked for more suitable means of expression. They adopted the interior monologue to represent in a novel the unspoken activity of the mind before it is ordered in speech. It is necessary to distinguish 4 kinds of interior monologue;
- Indirect Interior Monologue, where the narrator never lets the character's thoughts flow without control and maintains logical and grammatical organisation;
- Interior Monologue 1, characterised by two levels of narration, one external to the character's mind, the other internal;
- Interior Monologue 2, where the character's thoughts flow freely not interrupted by external elements;
- Extreme Interior Monologue where words fuse into others to create new expressions.