Spoken and Unspoken – The Grammarians by Cathleen Schine

Laurel and Daphne Wolfe are identical twins who are fascinated with words and grammar. Born in the 1950s, they grow up in a comfortable home in suburban Larchmont, NY, and while they are inseparable, and each other's closest friend, they are jealous and competitive.

Their mother, Sally, and father, Arthur, are a bit overwhelmed by their closeness, their secretiveness, and their quirky fixation on language. With Don and Paula, Arthur's brother and his wife, and their son Brian, the family is very insular.

One day Arthur brings home an immense dictionary, Webster's Second, and a special stand to hold it. It becomes a fascination, and much later, a weapon that tears the twins apart.

Laurel and Daphne come of age in the Reagan era, also the age of AIDS, in an un-gentrified New York, with all its grit, full of character, and characters. They share a walk-up apartment in the then-dangerous East Village, find jobs, and then husbands. Their relationship begins to unravel once Laurel and her husband have a child, but it ebbs and flows. Meanwhile, the husbands become the best of friends, despite the tensions between the sisters.

Through it all, Sally serves as the third major voice in the story, and a uniting thread. As the decades pass, and changes in the family occur, her point of view becomes cleverly dominant, which leads to a surprising, but satisfying resolution.