Here's why:
* Stream of consciousness: Darl's narration is often stream of consciousness, which allows for more unconventional and colloquial expressions to emerge.
* Metaphorical language: Darl frequently uses metaphors and similes that are distinctly his own, and sometimes incorporate slang elements.
* Focus on sensory details: Darl's narration often focuses on sensory details and experiences, which can lead him to use more evocative and informal language.
Other characters who use slang:
* Jewel Bundren: Jewel's language is often blunt and matter-of-fact, and he uses some colloquialisms.
* Anse Bundren: Anse uses a more traditional dialect, but he occasionally employs slang, particularly when he's trying to be persuasive.
* Cash Bundren: Cash uses a more technical vocabulary, but he does occasionally use slang, especially when interacting with his siblings.
It's important to remember that Faulkner's use of dialect and slang is a significant part of the novel's style and characterization. It helps to create a sense of authenticity and distance between the characters and the reader, and it also highlights the unique perspectives of each individual.