If there is one rule of thumb to keep in mind with rockers Roadkill Ghost Choir, it is that you should expect the unexpected.

"When we first started, we were pretty much an alt-country band; it was really, really twangy," says singer/guitarist Andy Shepard. "And then the first time we ever went to record for the band's 2012 EP, Quiet Light, the goal was to make an ambient John Prine record, which makes zero sense. I guess we definitely failed to do that on the EP."

Shepard punctuates this last statement with a laugh, which underscores the fact he is not concerned with meeting expectations, even his own. Instead, if anything, he prefers to push boundaries and let the creative process take him wherever it wants to take him. The band will bring its genre-twisting approach to the U.S. National Whitewater Center on July 5.

"As we've evolved, we've tried to keep it more experimental rather than just fitting into one genre, because it's boring when you have to perform to a certain standard," he says. "It gets old, and we realized that in the beginning, so we pushed ourselves to evolve into something that's more exciting for us to play and for people to listen to."

Enter Roadkill Ghost Choir's forthcoming full-length debut album, In Tongues, which comes out Aug. 19. Whereas Quiet Light fell somewhere between folk and Americana — think Matthew Perryman Jones with a bit more edge — Tongues dives headlong into rock 'n' roll territory.

"Slow Knife" is a groovy road rock track that is straight out of the Tom Petty playbook, while "HWY" is a galloping, star-scraping rock and soul number that finds Shepard giving his strongest vocal performance yet. Tongues was born out of a sense of displacement for the band and served as a way for them to anchor themselves again.

"We toured a lot in 2013, to the point where it was just too much," Shepard says. "You can only take so much of being in a hotel room every night with a bunch of dudes. So figuring out what home is and all the craziness of being in a band inspired a lot of the music."

But as the ambling rocker "Womb" demonstrates, life on the road is not the only thing that influenced the content of this record. With references from Jesus Christ to the Beast and the Whore in the Book of Revelation, the song shines more than a little bit of light on Shepard's religious upbringing and how he views that world now.

"I grew up in a religious setting, where I went to school and church and it was all connected," he explains. "There's a lot of asinine things, completely insane, that people will do based off of a book, so 'Womb' is my take on the terrifying nature of people and belief and how to find a middle ground that isn't so terrifying."

And if tackling such a personal subject is something Shepard is willing to do, you can bet that nothing is off limits. That should keep fans on their toes.