Joseph M. Romero’s “Life Among the Lexicographers” is a description of the Dictionary of American Regional English (DARE) and its creators, and it discusses both particular dialect terms and the decisions on whether to include them. This is a neat example of both:
When in doubt, DARE editors tend to err on the side of inclusion. Many words are amply attested—that is, there are plenty of recorded uses. Others appear only once. Should poorly attested words be excluded? The phrase trade-last, for one—meaning a kind of quid pro quo—”I’ll say something nice about you if you say something nice about me first”—is found scattered throughout the country, especially among older speakers. A regional variant, last-go-trade, is found in the middle and south Atlantic and has an entry of its own; but what about Alaskan trade, which means exactly the same thing but appears only once in the sources available to DARE? “It was important to include Alaskan trade even with only one instance, because it’s a wonderful example of the process of folk etymology,” says Hall. “Someone who is unfamiliar with the folk tradition of trading compliments hears the phrase last-go-trade, doesn’t quite understand it, and tries to make it meaningful by substituting a word that is familiar. Since Alaska is, to most Americans, a far-away and exotic place, it makes sense to the hearer that the unusual custom would be an Alaskan trade.”
(Via wood s lot, which has good links on slang as well today.)
The dictionary’s website is very informative, but I can’t (or don’t know how to) link to individual sections. If you’re interested in helping them with the fifth volume, click on the QUERIES link at the left and see if you know any of the terms they’re asking about, from slang-jang ‘A dish containing oysters, onions, pickles, peppers, etc’ to turkey apple, turkey haw ‘A hawthorn (Crataegus mollis).’ Your strange family word may be a lexicographer’s lemma!