COUNTRY ROCK: Borges covers X and Dolly Parton, and she serves up a few originals that could’ve been done by either.

For Bostonians familiar with her history, however, it’s notable that a former indie-pop singer should have become one of the city’s leading country voices. And if you’ve seen Borges perform, you know that’s even more surprising given how shy and self-effacing she used to be on stage. As the singer/guitarist of Kipper Tin — who played no-glory gigs around town for a good six years — Borges was charming and waifish but gave no clue to the brassy frontwoman she’s become.

You could waste time wondering whether Diamonds in the Dark, her sophomore disc on Sugar Hill, is a country or a rock-and-roll set — suffice to say that it has covers of both X and Dolly Parton plus a few originals that could’ve been done by either. (The radio track, a cover of the Reigning Sound’s “Stop and Think It Over,” is straight-up power pop.) Whatever you call it, this is vital, flesh-and-blood music steeped in barroom sweat and love/sex undercurrents, and a good antidote to the current drony, angst-ridden school of alt-country. Borges’s band — formerly the Confidence Men, now the Broken Singles — are as adept at straight-up twang as Crazy Horse guitar demolitions. Her voice is powerful throughout, but she never shows off her pipes at the expense of a lyric. Making a quick home-town stop between a run of tour dates, she and the Singles hit the Lizard Lounge this Friday and Saturday.

Over coffee at Carberry’s in Cambridge a week ago last Monday, Borges pondered her transformation. “I don’t feel any differently about myself; but I’ve gotten better at telling people about myself. I used to be afraid I’d make too many mistakes. Now I make tons of mistakes, but I know how to make them work. I learned a lot with Kipper Tin — I learned how not to talk between songs; I learned not to drink too much beer beforehand.” And the change in musical styles? “The crux of indie rock is that you’re supposed to be witty, you’re supposed to use metaphor. Not that I don’t love that kind of music, but my voice is a little better for what I’m doing now. It’s a thin line anyhow — I’ve always loved X, and they were partly a country band. And Chuck Berry has enough twang that he’d probably get considered country.”

She moved into country gradually, at first stepping up to do a few songs with her boyfriend Jake Brennan’s band. She and Brennan wound up settling into a Nick Lowe/Dave Edmunds–type arrangement, sharing the band and swapping the frontperson role. (Brennan recently got a gig in video production, so he’s putting music on the back burner for now, though he played on Borges’s disc and co-wrote one track.) And when she started writing for the Confidence Men, she approached it methodically: “It was like I went to the library and read all the books, then I wrote my own. You have your palette to work with: there’s drinking, religion, somebody losing someone. Then you find your own way into the genre, and I think the new disc reflects that. Songwriting to me has no logic to it. Sometimes I feel like a scientist: ‘Is the lighting right, am I sitting in the right chair?’ But you can’t force it to happen. And that’s definitely on my mind now that we’re starting to think about a third record.”

She doesn’t fancy herself a confessional songwriter, however, so don’t peruse the lyrics for clues about her personal life. The new disc’s opener, “The Day We Met,” is one of the giddier love songs in recent memory (“The day we met should be a holiday”), but it was written under mundane circumstances. “Fifteen minutes while the football was going on in the living room. It was your basic ‘sit down and write’ job, and the cliché is that happy love songs are the hardest ones to write. But there was no happy emotion coursing through my veins at that point.” The closest thing to a personal song, she notes, is “Belle of the Bar,” on which the fiddle and brushed drums conjure a closing-time mood. “You’re the good-time girl that everybody wants to hang out with, but nobody wants to make an honest woman of you. I think I was fully that when I was 25 [i.e., five years ago], and I put the age into the song.”

As a former high-school actor, she has a preference for dramatic-monologue-type songs that don’t necessarily match her own life. So she essays Dolly Parton’s world-weary “False Eyelashes,” even if she enjoys the spotlight a lot more than Parton’s heroine did. And the X song she does, “Come Back to Me,” is likely Exene Cervenka’s most difficult one, written after she lost her sister (though Borges treats it more as a break-up song). She got the stamp of approval at a recent Nashville show when she found the stage crashed by John Doe, even though the two had never met. “He scared the bejeezus out of me. At first I thought he was one of those crazy guys that jump on stage, so my first impulse was to whack him.”

That wasn’t even the wildest show she’s played. On a recent Southern stop, one fan who really wanted her attention ate a couple of her tour buttons. And there was a show in Providence where she knocked herself with a guitar before going on stage and went on with half a front tooth. “That took care of my appearance for the night. Though we had a couple of weirdo guys who thought it was hot.”

SARAH BORGES | Lizard Lounge, 1667 Mass Ave, Cambridge | January 18-19 | 617.547.0759