In 2014, Meghan Trainor was “All About That Bass.” But back in 2011, she was all about that acoustic pop.

The golden-haired singer, whose breakout single has been watched on YouTube more than 600 million times, released three albums on her own before she got signed by Epic Records. Her early stuff sounds like the work of the precocious teen that she was at the time — sweet and earnest, the pop equivalent of Starbucks’s Blonde Roast — but it’s more notable for what it lacks: Trainor’s current-day accent. The one that transforms “that” to “dat” and seems partial to the term “booty.”

Trainor’s dropped G’s are a put-on, in the same way white rapper Iggy Azalea turns her Australian vowels sideways when she steps into a recording booth. But the most curious thing about Trainor’s phony accent isn’t that she has one, but that she keeps it going outside of her raps. It’s there in her interviews. On NPR, faintly. And in concert, at Fillmore Silver Spring on Sunday night, in front of fans who probably look a lot like the people Trainor grew up with on her native Nantucket Island.

“I know you be textin’ at 3 a.m.!” Trainor crowed from the stage, segueing into “3AM,” one of numerous cutesy ditties found on her wildly successful debut, “Title.”

But Trainor’s verbal shtick ranks as her second most consistent feature. First is her solid vocal ability. Despite an illness that she said forced her to drop into a lower register, Trainor’s voice sparkled almost as much as the bejeweled mike she poured it into. A vivacious band and backup dancers helped bang out a compact hour-long set, making her bubblegum songs feel more like a meal.

Meghan Trainor performs on Feb. 7 at the 2015 Clive Davis Pre-Grammy Gala show at the Beverly Hilton Hotel in Beverly Hills, Calif. (Paul A. Hebert/Invision/AP)

If only Trainor would dial back the doo-wop. I know, criticizing doo-wop seems like questioning the merits of a rainbow. But is this innocuous vintage pop really the best style for her? Yet she relies on it as much as the grocery-aisle feminism of tracks like “Title” and “Dear Future Husband.” Amy Winehouse made that sweetness sound troubled; Lily Allen made it wry. Trainor makes it sound like Disney.

Which is not to say that Trainor doesn’t work like a grown-up. After a costume change, a dance-off to Mark Ronson’s “Uptown Funk,” a party-rocking “Bang Dem Sticks” and a soca throwdown — complete with matching fake accents — she looked tired but would not disappoint the little girls at stage right clamoring for the song they came for.

Trainor closed with a gently wilted “All About That Bass.” It’s hard to say whether she seemed drained because of her sickness or her fatigue with the song that made her famous. But without her own exclamation points to end the sentence, she fell back on confetti cannons. Like Trainor’s music, they’re a simple pleasure. But she could do better.

Schweitzer is a freelance writer.