What unique words do they use in Maryland, Virginia and Washington? Or, for that matter, why do the same things have so many different meanings, depending on whether you are on the Jersey Shore, the Upper Peninsula or Fisherman’s Wharf?

Jim Leach, chairman of the National Endowment for the Humanities, is only one of many NEH leaders who have supported the Dictionary of American Regional English over the decades. (POWERS AND CREWE PHOTOGRAPHY)

Fifty years ago, scholars at the University of Wisconsin-Madison set out to document the regional speech of the United States. They interviewed people one-on-one. They read cookbooks, poems, newspapers and novels. This week, the fifth and last volume of the Dictionary of American Regional English was published, making it the most exhaustive record available of American speech.

The project is known to linguists as DARE and the last volume covers ”slab” to “zydeco .”

The scholars, led by chief editor Joan Houston Hall, culled their interviews and other research down to 60,000 entries. The project was founded by Frederic G. Cassidy in 1962.

At a recent meeting at National Endowment for the Humanities, Hall promised that the work would continue and said she is intrigued by the language popping up on Twitter and other social media. Digital resources added to the research timeline. “With the last decade, there was so much of value we couldn’t ignore it,” said Hall.

In the bound version, each entry includes a detailed history of the word. “Soda” or “pop”? Very, very early soda was sody-water. That was 1834 in New England. By 1974, soda was pop in most areas of Wisconsin but soda across Milwaukee. “Vacation” has been adapted by some segments of society to mean time spent in jail. The dictionary also digs deep into pronunciations — and “umbrella” has one of the longest explanations.

What also sets it apart, said Ben Zimmer, the executive producer of Visual Thesaurus and Vocabulary.com, is a sense of discovery and familiarity. These are words and expressions, he said, that “you are not going to find in other dictionaries.”

In addition to pleasing word-lovers and historians, Hall said the project has helped to explain regional phrases that creep into public speeches — and also crimes. A child abductor had used the phrase “devil strip” to describe where to put a ransom. With the help of the DARE staff, the phrase was narrowed down to one used in Akron, Ohio, for the grass between the sidewalk and the street. The suspect was caught.

DARE is the longest continuously funded project by the NEH, which has contributed $10.4 million to it since 1970, with additional funding coming from foundations, government agencies and individuals. The book, an arm strengthener at 1,244 pages, is published by Harvard University Press. Next year, the press promises to put the whole kit and caboodle on line.