In the play Trifles, how is the dialogue important?
The dialogue in Trifles is intended to be naturalistic and plain, the sort of speech that would be used by working-class men and women of the time. There is no flowery prose and few "big" words, showing pragmatic education over superficial education. By showing how the women -- who the men dismiss as only being concerned with "trifles" -- discover the motive and purpose of the murder, the play shows how fancy and highly stylized dialogue is unnecessary in creating suspense and intrigue:
MRS. PETERS: [To the other woman.] Oh, her fruit; it did freeze. [To the LAWYER.] She worried about that when it turned so cold. She said the fire'd go out and her jars would break.
SHERIFF: Well, can you beat the women! Held for murder and worryin' about her preserves.
COUNTY ATTORNEY: I guess before we're through she may have something more serious than preserves to worry about.
(Glaspell, Trifles, etext.virginia.edu)
This exchange is typical in the story. Some of the dialogue sounds forced and "clunky," but this is deliberate; people talking without a script never sound like snappy dialogue that has gone through multiple revisions. The simplicity of the dialogue highlights the simplicity of the people; they are not concerned with lofty, literary ideals, but instead with the matter at hand. Instead of unnecessary monologues about the state of humanity, the women think back to specific events, piecing the murder together from their shared experiences.