Little less conversation.

Here’s an amusing coincidence. “Little,” which is a reversal of the Tom Hanks classic “Big,” was written by Tina Gordon Chism, who also wrote “What Men Want,” a reversal of “What Women Want.” Chism’s niche, apparently, is mediocre rewrites of fantasy comedies where the premise is reversed and the main characters are black women. All of which is fine except for the “mediocre” part.

“Little” (which Chism also directed) begins with sweet 13-year-old Jordan Sanders (Marsai Martin) being bullied in middle school but reassured by her parents that her intelligence will be an asset when she grows up. She’ll be the head of a company someday, and nobody bullies the boss.

In the present day, adult Jordan (Regina Hall) has taken that sentiment to heart. She runs a booming Atlanta tech company, has more money than she knows what to do with, and is a total bitch to everyone she meets. She’s demanding, like “tell the housekeeper to put my slippers exactly 53 centimeters from my bed” demanding. It’s shades of “The Devil Wears Prada” when her employees sound the alarm and scatter for cover when she arrives at the office. She’s especially mean and unreasonable with her timid assistant, April (Issa Rae), a wilting flower who doesn’t stand up for herself with anyone, let alone Jordan.

After being rude to a little girl who then waves a pretend magic wand and curses Jordan to be a kid again, Jordan does indeed wake up as her bespectacled, bushy-haired, 13-year-old self. A nosy neighbor sees a kid in Jordan’s penthouse apartment and calls Child Protective Services (in the form of Rachel Dratch), so next thing you know Jordan is back in middle school — the very same middle school she was bullied at 26 years ago.

Meanwhile, April has to go to the office and fill in for Jordan (who’s said to be out sick). Her lack of confidence initially makes her a doormat, but soon the employees start responding positively to her friendlier, less terror-based managerial style.

Most of the comedy (such as it is) is centered on the dynamic between April and Jordan. Jordan is still the boss, but out in the world April has to take control and act like the girl’s “auntie.” When Jordan’s regular hookup, Trevor (Luke James), comes a-callin’, Jordan and April scramble like flustered idiots to concoct a cover story before landing on young Jordan being other Jordan’s daughter, heretofore kept hidden from Trevor because Jordan is secretive.

“Flustered idiots” describes their behavior much of the time. As is often the case with feeble comedies about people pretending to be something they’re not, this one reaches for laughs by having Jordan continually forget that people are seeing a 13-year-old girl and not a 39-year-old woman. So somebody asks what she’s doing in this luxurious apartment, for example, and she indignantly answers something to the effect of, “It’s MY apartment! I bought it with my money because I’m a rich boss lady!” Then she catches herself, hems and haws, and sputters out a suitable lie. She does this CONSTANTLY. Every 30 seconds or so her memory resets and she forgets she’s a little girl now. It’s grating, lazy humor. (In her defense, everyone she encounters is too dumb to realize anything is amiss.)

I’ll say this, though. Chism’s screenplay may be pale and tired, but 14-year-old Marsai Martin (from TV’s “Black-ish”) is a firecracker. She’s convincing as a supercilious woman in an awkward teen’s body and easily holds her own in every scene. She’s actually better than Issa Rae, who can’t do much with her weak, mousy character. Give Martin something other than bland piffle to perform and I bet she kills it.

Crooked Marquee

C (1 hr., 48 min.; PG-13, some innuendo, mild profanity.)