“Adam’s off ox” is one of the phrases included in the Dictionary of American Regional English, Volume I: Introduction and A-C , part one of a multivolume effort to capture regional expressions.
The DARE project, as it is known, was initiated in the 1950s by Frederic Cassidy, a well-known linguist who sent field workers out across the country in “word wagons” to interview people. Cassidy’s catalogers talked to nearly 3,000 people over six years, making recordings along the way in order to capture pronunciations.