A Clockwork Orange (1962)

Alex's invented slang, Nadsat, makes violence sound like a performance he wants the listener to enjoy. Learning its rhythms is inseparable from noticing how his language distances him from other people's suffering. The voice is memorable and morally repellent, with sexual assault and severe violence throughout. Choose the original 21-chapter text if you want the complete British version; the early American edition omitted its final chapter, so edition choice materially changes the book.