Olivia Colman, left, and Jessie Buckley star as warring neighbors in the dark comedy "Wicked Little Letters." (Parisa Taghizadeh/Sony Pictures Classics)

The “Wicked Little Letters” start arriving even before the dark comedy has begun.

The movie is about the escalating battle between prim Englishwoman Edith Swan (Olivia Colman), who is given to remarking that suffering is a gift because it strengthens her, and new neighbor Rose (Jessie Buckley). Edith pretends to like Rose, in the same way she pretends to like suffering, but there are plenty of reasons to feud with her neighbor: She is Irish. She is a single mother who lives with a Black man. She is loud (some of that involves the man). She swears like a sailor would if he dropped an anchor on his foot. She drinks. And she isn’t especially tidy.

Inspired by events that happened in an English village in the 1920s, “Wicked Little Letters” is an “Odd Couple” situation and the two leads are spectacular. The stakes get high quickly — someone (possibly Edith) reports Rose to child protection authorities, which leads to her being jailed. Meanwhile, the acts described in the profane letters Rose receives, and seems to relish reading aloud, get increasingly vile and physically impossible.

A big part of the appeal of “Wicked” is its leads, who also shared billing (and Oscar nominations) in “The Lost Daughter” but did not share the screen, since they played the same woman at different stages of life. Both actors are adept at cluing us in that there’s more to their characters than what’s on the surface, which makes their many scenes together especially good.

We know there are secrets, even if we don’t know what they are, and we suspect that buttoned-up Edith and knicker-free Rose might be more similar than either would care to admit. Buckley’s ferocity often hides her characters’ vulnerability (as in “Women Talking”), which Rose eventually reveals. And Colman’s half-concealed smiles let us know Edith, who still lives with her domineering parents, gets a bang out of the nasty language. It’s almost as if, as in “Lost Daughter,” the two are in separate stories that turn out to be the same story.

I suspect “Wicked” might have felt one-note if those two were all it had going for it but a zesty supporting cast fills in additional colors. There’s a Greek chorus of villagers — played by, among others, Anjana Vasan, Hugh Skinner (playing a guy even dumber than the one he played in sitcom “W1A”) and the legendary Eileen Atkins.

Their shifting takes on the poison-pen letter situation keep us interested in the mystery of who’s sending them while also contributing to what turns out to be the theme of the movie: that women in ‘20s England were desperate to get out of the boxes society thrust upon them, whether they were a belittled police officer with no authority (Vasan) or a single mom, trying to raise her kid under the disapproving eye of her bored neighbor.

About an hour into “Wicked,” we find out who sent the letters. You may have guessed by then; it wouldn’t take Selena Gomez to get to the bottom of this one. But the movie actually gets richer once we know what’s going on. Like many villains, this one doesn’t think of themselves as a villain. They’re just dying to be heard in a world where no one cares what they say.