Actor/playwright Danai Gurira begins both acts of her explosive “The Convert” with characters speaking the Shona language, which she knows few theatergoers will understand. It’s a really smart choice.

For one thing, the acting in director Wendy Knox’s restrained production of “The Convert” is so fine that we don’t need the words. But the Shona establishes that some of the characters believe things that they do not have to share — things that are a part of them and that they are afraid could be taken away.

Those words are an early announcement, in a play concerned with colonialism, that there are ideas, places and people that are not ours to understand or consume.

“The Convert” is set in 1895 in southern Africa, in what is now Zimbabwe, which is where Gurira, who went on to star in “Black Panther” and “The Walking Dead,” grew up. All of the characters are black but they fall on a continuum of beliefs. Chilford (Yinka Ayinde) is a Roman Catholic dedicated to converting others to his faith, presumably learned from (or perhaps imposed on him by) British missionaries. His housekeeper, Mai Tamba (Ivory Doublette), attempts to follow his Christian teachings but secretly practices the ways of her ancestors.

A newcomer, Jekesai (who is renamed Ester), seems to be that rarity: a true believer who finds a way to embrace both the faith she grew up in and the one that Chilford teaches her, emphasizing what is central to each: “seeking peace and loving one another.”

Jekesai is the play’s title role and, although there are parallels to “Pygmalion,” her searching and calm insistence on the rightness of her path — embodied in the shimmering clarity of Ashe Jaafaru’s performance — makes her like no character you’ve ever seen in a play.

Gurira’s dialogue sometimes gets didactic and the play is unwieldy — it has three acts but Frank Theatre (which previously produced her “Eclipsed”) only uses one intermission, making for a long second “half.” But the Macalester-educated playwright, whose middle name is Jekesai, gives voice to characters we’ve never seen on stage and she takes the time to explore the complex sequence of events that have brought them into conflict, as they become ensnared in an uprising at a nearby mine.

Gurira has fun with Chilford, for instance, whose English is excellent but whose command of idioms is not. That comedy gives her an “in” to investigate the plight of a man of faith whose people consider him a “bufa,” or traitor. Is Catholicism central to who he is, or has he been conned into believing?

If his faith is crucial to Chilford, shouldn’t the same be said for the ancestral ways of Mai Tamba and her peers, whose beliefs go back centuries farther than Chilford’s? How does all of this relate to the fact that the British, frankly, do not belong here in the first place? And why do we assume a play about Africa will be in English, anyway?

Even the format of the play, which follows the classical conventions of drama, seems to interrogate these questions. “The Convert” and, indeed Gurira’s career, might not exist in the way it does if it weren’t for colonialism. So it makes perfect sense that she reserves at least parts of her play for Africa, as if to say, “This part is for me and mine.”