Mencken was inspired by "the argot of the colored waiters" in Washington, as well as one of his favorite authors, Mark Twain, and his experiences on the streets of Baltimore.

Mencken eventually asked "Why doesn't some painstaking pundit attempt a grammar of the American language... English, that is, as spoken by the great masses of the plain people of this fair land?"

Mencken assaulted the prescriptive grammar of these critics and American "schoolmarms", arguing, like Samuel Johnson in the preface to his dictionary, that language evolves independently of textbooks.

Many of the sources and research material associated with the book are in the Mencken collection at the Enoch Pratt Free Library in Baltimore, Maryland.

Mencken released two full-sized Supplements to the main volume, in 1945 and 1948, based on the boom in linguistics articles.