LIVING WITH WAR A Belfast Year By Sally Belfrage Elisabeth Sifton/Viking. 303 pp. $19.95

Craic is the word in Irish, "crack" in English. The pronunciation in the two languages differs slightly, but the meaning is the same.

A wisecrack can be part of it where I live, in quiet southwest Kerry, in the Republic; likewise among people of every persuasion (Protestant or Catholic, Unionist or Nationalist, paramilitary or nonviolent) in unquiet Belfast, in Northern Ireland. According to Eric Partridge in "A Dictionary of Slang and Unconventional English," the word encompasses "the latest news, gossip, anecdote." Crack, in short, is talk. The talk, along with the pint, we go to the pub for. The talk, along with the cup of tea in neighbors' kitchens, is about "what's strange" (meaning, what's new).

Talk. The all-Ireland sport. In "Living With War" Sally Belfrage recognizes its importance in present-day Belfast, where, unfortunately, the warring communities talk ceaselessly among themselves in their separate neighborhoods, clubs and pubs, but very little to each other. A pity she is wrong in her assertion that "there is no direct translation" of the word -- and in the impression she leaves that the use of language that delighted her in the Northern Ireland capital is peculiar to that beleaguered city.

The Belfast accent (there are several variations of it) is unique. The idiom is not. Many of the phrases Belfrage recorded during a year in intermittent visits to Belfast enliven the crack elsewhere -- in the 26 counties of the Republic across the 300-mile border, as in the six that remain British. Everywhere the yarn begins, "C'mere till I tell ye." Everywhere "your mon" who has "not a titter of wit" spends his dole money getting "poleaxed" or "arsified." Couples "licit" or otherwise are said to be "doing a line" in Cork and Dublin and, it's my guess, in County Mayo, where the author (a California-born Londoner) once vacationed. I can only think that she was not listening as hard on holiday as she did for this book.

Listening and eliciting a range of emotional responses from all sorts of people is a skill Belfrage has been honing since publication of her first book, "A Room in Moscow," written when she was 21. She combines intellectual objectivity with the courage not to distance herself from her subjects or to hide her dismay at some of what she hears and sees. The effect here is to make the men, women and children of Belfast leap to life. Especially the children, few of whom have known a world without plastic bullets and the rumble of Saracens (British armored personnel carriers) down the mean streets where they live.

In "A Place Apart," Corkwoman Dervia Murphy wrote: "The Northern Irish may not be comprehensible, but they are very addictive." Belfrage conveys this sense of them as successfully as her predecessor in the field. Some of her statements and judgments may be open to question, but what reader will soon forget the Mullins family, with whom she stayed in the Catholic slum of Andersonstown? (Once the poorer sections of the city had mixed populations. Older people recall that they "rubbed along" quite well together. Now these neighborhoods, like almost all the schools, are segregated.)

Sinn Feiner Brendan Mullins is unemployed and tubercular, his family so poor that when Belfrage borrows a towel, having forgotten her own, she discovers at the end of a week that it is the only one they possess. Yet there is "constant touching and hugging for the children, an open door for friends to come in, adventures going by the window as the army patrols circle or the neighbours clobber each other on the pavement again (even more entertaining than 'Dynasty')."

Or there's the feminist Hester, a leading figure in the UDA (Ulster Defense Association, the largest Protestant paramilitary organization), who bows her head but clenches her fists during the playing of "God Save the Queen."

All but a few of the people the author met seem to thrive on the invidious excitement of war, though they worry about their children's future and about the spread of Mafia-like protection rackets in both communities. None sees an end to the present conflict, about to enter its 20th year.

Nor does Sally Belfrage. Her succinct introduction provides a clear summary of the 800-year background to "the Troubles." But in conclusion she can only write: "The overwhelming feeling I got in Northern Ireland was that the war is going to continue because so many {have} a personal stake in it. For some the stake is idealism, for some it's personal profit, for some it's power ... For a kid-rioter of my acquaintance, it's just the crack."

The reviewer divides her time between County Kerry, Ireland, and Hanover, N.H.