Atherton's book is "absotively" wonderful. Appreciating the Wake certainly requires this book. Numerous linguistic influences on Joyce from various authors are catalogued. Particularly interesting is the lengthy analysis of Lewis Carroll's literary influence on Joyce:
1. Carroll is presumably the undisputed inventor of the portmanteau word - a word packed with multiple meanings. Carroll was content to have dual meaning but Joyce packed as many meanings as possible into his words.
2. Carroll (like Joyce) worked with successive alterations of one letter in a word - meat, meet, mate, maze, etc. Sections of the Wake which obliquely referenced Carroll would routinely incorporate this technique.
3. Alice served as an alterego for Joyce's heroine ALP, where "Wonderlawn" is code for the Garden of Eden.
In short, Joyce found much in Carroll's work that (in the case of the portmanteau word, to his surprise) neatly "dovetallied" with his own "work in progress". The Books at the Wake is a fascinating and well-written collection of many more such analyses (Shakespeare, Blake, Vico, etc.).