NONFICTION : AMERICAN REGIONAL DIALECTS, A WORD GEOGRAPHY by Craig M. Carver (University of Michigan: $29.95; 317 pp.).

What a delight it is to come across words I haven’t heard in half a century! Like tarvia for a road surface or piazza for a veranda. This collection of words from different regions of the country is a history as well as a geography, and it is fascinating to discover, for instance, that there were once tiny New England enclaves in Cane Creek and New Garden, N.C.; Dorchester, S.C., and Midway, Ga.

Californians will be interested to learn that banquette means sidewalk in the South and that tule is derived from the Nahuatl tullin for bulrush. And who would have thought that what we call the median strip of a freeway is known in Louisiana as neutral ground ?

I protest some misspellings (alotted and descendents) and the inaccurate Sears & Roebuck, and I question calling poor boy sandwich a Northern usage when it is described by others as having originated in Louisiana.

But Carver is on solid ground when he points to the “unsettled and heterogeneous dialect situation” of Southern California, where he cites such Spanish words as mesa, arroyo, ramada and patio. Yet he has ignored home boy, which is becoming increasingly popular.