The Lady Train teammates don’t merely play basketball. It’s how the Arkansas high schoolers talk.

Line after line of dialogue in “Flex,” written by Candrice Jones, gets a parenthesis translating text into basketball lingo. For instance, “My bad. Come on” is “giving an assist,” while “I felt somethin’” is “staying out of bounds.”

Similarly, in San Francisco Playhouse’s production, when Starra (Santeon Brown) says the girls’ futures are “riding on” whether they play in a state tournament, she’s “calling the play.”

But for all her moxie, Starra’s still learning that the Lady Train is not exempt from the rules of the game.

For one, a senior on the team gets pregnant every year like clockwork, and no one, even one a star like April (Camille Collaço), can play while pregnant. Another, as Donna (Courtney Gabrielle Williams) puts it: “They get mad if you make the baby ’cause the babies cause so many problems, but they get even madder if you say you don’t want the baby.”

Then there’s the heartbreaking truth, conveniently ignored by pretty much every sports movie, that not every talented student can be recruited by a Division I school.