Riddley Walker

A novel by Russell Hoban, set two (or perhaps three) millennia After the End.

Like A Canticle for Leibowitz, it deals with quasi-religious themes and ancient nuclear weapons. Unlike Canticle, it's about as pellucid as a brick, being written in what the author thinks English may evolve into 2000+ years down the road; understanding some of the passages can give even die-hard Finnegans Wake fans a run for their money. It's drenched with symbolism and double (or even triple) meaning, and is a favorite of those literature professors who have to teach a course in Science Fiction literature.

This novel contains examples of:

 * Eternal English: Averted, and oddly, played straight. English at the time of the novel is phonetic and twisted compared with 21st century English, but it is more like 21st century English than the "old language" in which "The Story of Eusa" is written. This implies that, after a millennium or so of linguistic drift made English almost unrecognizable, another millennium of linguistic drift undid some of the previous changes.
 * Funetik Aksent: The form of English used in the book is actually based upon phonetic interpretations of the Kentish accent.
 * Hit So Hard the Calendar Felt It: Dates are reckoned in years O.C., which means "Our Count."
 * Nu Spelling: The entire book.
 * Punch and Judy: The biggest part of contemporary culture that survived to the time of the story. They are treated almost as religious figures.
 * Scavenger World
 * Shrouded in Myth: The pre-apocalypse world.