The actress won a 1979 Tony Award for Best Actress in a Play for portraying a stroke victim whose world — and speech — is broken and fragmented in Arthur Kopit's Wings.
Ms. Cummings was born Constance Halverstadt. Her father was a lawyer. Her mother's maiden name was Cummings.
She made her stage debut as the Prostitute in a San Diego stock production of Seventh Heaven in 1926. She toured in the chorus of the Gershwin musical Oh, Kay! in 1928 and made her Broadway debut in the chorus of the Gershwins' Treasure Girl. Other Broadway credits include The Little Show, This Man's Town, June Moon, Madame Bovary, One-Man Show, Accent on Youth. She made her London debut as Alice Overton in the Repertory Players production of Sour Grapes in 1934.
Her motion picture credits include Harold Lloyd's "Movie Crazy," "Broadway Thru a Keyhole," "Glamour," "Looking for Trouble," "Washington Merry-go-round," "American Madness," "The Criminal Code," and Noel Coward's "Blithe Spirit," directed by David Lean, among many other movies and TV appearances.
England embraced her work, and she was a major star of the British stage. She starred as Mary Tyrone opposite Laurence Olivier in a National Theatre staging of Long Day's Journey Into Night, which was also seen in a TV version. She was lauded for her work as Martha in Who's Afraid of Virginia Woolf? in England in 1964.
She met her future husband, British playwright Benn Wolfe Levy, while in Hollywood. She would appear in (and hone her stage skills) in his plays. They wed in 1933 and later had a son and a daughter. Her husband died in 1973.
Among her major credits on the British stage are Katherine in Goodbye, Mr. Chips, Juliet in Romeo and Juliet, Miss Richland in Oliver Goldsmith's Good-Natured Man and the title role in Bernard Shaw's Saint Joan. In her later career, she appeared as the cruel Inez in Jean-Paul Sartre's Huis Clos (No Exit), Ranevskaya in Michael Blakemore's revival of Chekhov's The Cherry Orchard, Agave in Wole Soyinka's The Bacchae and Gertrude in Hamlet. She appeared at the National Theatre for three years when Olivier was its director.
Ms. Cummings was made a Commander of the Order of the British Empire, or CBE, in 1974.
Her last film credit, according to Internet Movie Database, was the 1986 TV mystery "Dead Man's Folly," also known as "Agatha Christie's Dead Man's Folly."
She is survived by her son and daughter.