The poet Wallace Stevens coined the clause “the words of things entangle and confuse,” and while words have always served as something of an obstacle for the director Jeffrey Blitz — the man behind the 2002’s “Spellbound,” which in its own way redefined the popular potential of the documentary — they also have helped form the cornerstones of his young career.

Born with a stutter, a speech impediment with which he struggles to this day, Mr. Blitz, whose first dramatic film, “Rocket Science,” makes its New York premiere next Friday, said the challenges he has faced with the simple act of speech have informed his worldview and, not surprisingly, molded his interests as a filmmaker.

“It’s true, I did and I do stutter, [though] it’s very circumstantial,” the director said via e-mail, his preferred method of interviews. “Some situations, I’m perfectly fluent, and others I can barely get a word out. The most obvious connection to my work now is that I’m a real word lover. I love the power of specific words. That, in part, attracted me to ‘Spellbound,’ and, as you’ll see in ‘Rocket Science,’ the power of words and speech is really on display.”

“Rocket Science,” which was a smash hit at the Sundance Film Festival, earning Mr. Blitz a narrative directing award, centers around a high-school debate championship, much as “Spellbound” shone its spotlight on the national spelling bee. But rather than focus on the insider culture — the kids and parents who obsess day and night — “Rocket Science,” which is Mr. Blitz’s first dramatic feature, focuses on a stuttering boy who wants to join the team at his local New Jersey high school so he can impress a girl. It’s a fish-out-of-water story that makes more sense than you might think.

“As a stuttering kid, you learn tons of words because you need to be able to substitute words as you speak, trading out words you get stuck on for words you can say,” Mr. Blitz said. “I think you develop a real admiration for the power of words that fluent kids might not come to.”

Like such other recent young heroes as Max Fischer in Wes Anderson’s polished and preppy “Rushmore” and Jarred Hess’s awkward and aggressive title character in “Napolean Dynamite,” the hero of “Rocket Science,” Hal Hefner (played by 18-year-old Reece Thompson), breaks the mold of the average high schooler. Hal’s stutter has come to dictate his personality, and he walks through the halls with his shoulders slumped, his hair uncombed, and his hoodie sweatshirt sagging. Struggling to ask for pizza in the school cafeteria, and staring in awe as his debate team partner — yes, that girl — offers arguments in rushed, flowing sentences, Hal fights through his word fragments and breathing exercises, desperate to push his way into the school’s mainstream.

There are times in the movie when his stutter is uncomfortable to watch, so convincing and agonizing a condition that one is led to wonder whether Mr. Thompson stutters in real life.

“That’s a flattering question,” Mr. Blitz said. “No, Reece didn’t actually stutter. We called in a speech language pathologist for a day to teach Reece the mechanics of stuttering and then, because I had patterned Hal’s stutter after my own, I guided him as we were shooting. One of the approaches I took with Reece was to tell him the word that wasn’t in the script that he was trying fiercely to say. It gave him an internal process — a word he was thinking hard about but not able to convey.”

It wasn’t just the stutter that Mr. Blitz modeled after himself. As a high schooler, he too joined the debate team, though he did not have the conflicted romantic emotions that throw Hal into a period of emotional turmoil, despair and, eventually, enlightenment.

Some have suggested that Mr. Blitz modeled his film to fit the “Napoelan Dynamite” trend of modern tales about awkward teens, but the director points back beyond the rise of Mr. Anderson for the source of his inspiration. “I looked to those great comedies directed by Hal Ashby: ‘Harold and Maude,’ ‘Shampoo,’ ‘Being There,’ ‘The Last Detail.’ Ashby doesn’t have contempt for his characters at all. Even when they behave badly, as in ‘Shampoo,’ there’s an underlying compassion for them.”

It was Mr. Ashby’s sensibilities, combined with Mr. Blitz’s instructive first-hand experience of filming “Spellbound” — not to mention a fortuitous moment at the Los Angeles Film Festival, when an HBO Films producer fell in love with “Spellbound” and took a meeting with the director — that led Mr. Blitz to start contemplating what would become his fictional debut. “When working a documentary, you’re at the mercy of the world,” he said. “But I was constantly left wondering during the shooting of ‘Spellbound,’ What if? What if I met a different sort of kid? What if the story had gone this way instead of that? I think ‘Rocket Science’ became a way for me to answer those questions. I didn’t have to keep my fingers crossed that life would unfold a certain way. I could move it there myself.”

But in shifting the conversation from capturing real life to the concerns of a fictional endeavor, Mr. Blitz said he was again confronted with the challenge of words, forced to master a new vernacular, as he collaborated with a full film crew for the first time. “In fiction film, you constantly have to express what you want,” he said. “And the language you use to speak to the cinematographer is different than the language you use to speak to your actors, and that’s different than the language you use with your producers. There’s so much effort put into explaining what you want.”

So much, in fact, that Mr. Blitz plans to return to the documentary realm for his next film, a story about lotteries and their winners. Determined to plant his feet in two different worlds, and now with a smash-hit documentary and an award-winning feature to his name, Mr. Blitz said he wants to find ways to rise above the love-hate relationship that can accompany each filmmaking form.

“I’d love to go back and forth,” he said. “When you work on a documentary, you kind of hunger for more control over your story and for a bigger crew to help you achieve it. When you work in fiction film, you long for more spontaneity and a smaller, more efficient way to work. So they kind of continually rise to one another. I think when you work in documentary you’re always ready for the happy accident — you rely upon it, in fact. That ability to roll with the punches is a great thing to bring into fiction work: You’re always keeping your eyes open for the unexpected.”