I’ll bet I’m not the only moviegoer who saw The Legend of Tarzan this summer and came away disappointed that I never heard the famous Tarzan yell. It’s been a mainstay of those king-of-the-jungle stories from the earliest days of sound through the 1999 Disney animated feature. It also remains a popular part of comedienne Carol Burnett’s repertoire.

On the other hand, it has been reported that the descendants of Edgar Rice Burroughs, Tarzan’s creator, were happy with the half-hearted meow that took its place. Why? Because it was more faithful to the way the author first described it. Hollywood’s yodel-like call has been aped by countless kids over the decades; the new version may be more authentic, but it isn’t much fun to imitate. (The Burroughs estate isn’t foolish, however: They own a trademark on the Johnny Weissmuller version.)

Many of film’s most famous utterances didn’t come from the original books or plays at all, whether it’s the Tarzan yell; “Nobody puts baby in a corner” from Dirty Dancing; or Arnold Schwarzenegger’s defining phrase “I’ll be back” in The Terminator. Some famous dialogue does have a literary pedigree, however. “Frankly, my dear, I don’t give a damn,” which Clark Gable (as Rhett Butler) famously said to Vivien Leigh (as Scarlett O’Hara) in Gone With the Wind, was voted the number one movie line of all time in a 2005 American Film Institute poll. It’s almost exactly what Margaret Mitchell wrote in her 1936 best-seller, although screenwriter Sidney Howard added the clincher, “Frankly.” And while a team of scribes collaborated on 1939’s The Wizard of Oz, it was the story’s author, L. Frank Baum, who wrote the immortal words, “Toto, I have a feeling we’re not in Kansas anymore.”

Many memorable lines come right off the printed page, but it’s the way the actors say them that stays with us. It’s difficult to imagine “I’m gonna make him an offer he can’t refuse” except as it was articulated by cotton-jowled Marlon Brando in The Godfather. Neither Brando nor author Mario Puzo could have foreseen that the expression would enter our vernacular.         

Many memorable lines come right off the printed page, but it’s the way the actors say them that stays with us.

Ronald Colman — my wife’s favorite actor from Hollywood’s Golden Age — had the good fortune to deliver Sydney Carton’s closing speech in Charles Dickens’ A Tale of Two Cities: “It is a far, far better thing that I do, than I have ever done; it is a far, far better rest that I go to than I have ever known.” No one could have read those words more beautifully. They made such an impact that nightclub mimics got years of mileage out of imitating Colman performing them.

In the same vein (pun intended), anyone who parodies the character of Dracula with a bobbing, melodic Hungarian accent isn’t really parroting the immortal vampire: They’re imitating Bela Lugosi, who immortalized the character in the 1931 movie Dracula. Lugosi had created the part on Broadway in a successful adaptation of Bram Stoker’s novel, but it was the screenwriters of the 1931 movie who had him say, “I never drink … wine.” According to horror-film scholar David J. Skal, the phrase was so closely identified with the character — and Lugosi himself — that it was added to revivals of the play in which the actor toured for years. So distinctive was his Dracula that it spawned a catchphrase the actor never even uttered — “blah blah blah!” — a creation of comics lampooning Lugosi.

I suspect that today’s readers who go to see their favorite novels on film, from Twilight and the Harry Potter series to Gone Girl and Fifty Shades of Grey, are more interested in overall fidelity to the source material than notable bits of dialogue. What’s more, great dialogue isn’t as highly valued as it was in years gone by. Ever since Clint Eastwood muttered, “Go ahead, make my day” as gun-toting cop Dirty Harry in 1983’s Sudden Impact, screenwriters have struggled to come up with catchphrases for larger-than-life action heroes — some better than others. But a zippy slogan like “Hasta la vista, baby” or “Yippee-ki-yay, motherfucker,” snappy as it may be, can’t compare to Bette Davis (playing Margo Channing) warning her party guests, “Fasten your seat belts. It’s going to be a bumpy night” in Joseph L. Mankiewicz’s highly quotable All About Eve.

Still, every now and then, a writer can hit pay dirt with a clever turn of phrase. Drew Goddard hewed closely to Andy Weir’s novel The Martian but added one resonant line when he had Matt Damon (as the stranded but highly resourceful astronaut) say out loud, “I’m going to have to science the shit out of this.” It may not be elegant or even a good use of English but it’s clever, appropriate, and funny all at once. Author Weir approved.

Sometimes a literary property — be it current or a classic — is just the foundation on which a script is built. That was the case with the picture often cited as the definitive film noir, Double Indemnity. It was based on a book by James M. Cain (who also wrote Mildred Pierce and The Postman Always Rings Twice), and the repartee between insurance man Fred MacMurray and femme fatale Barbara Stanwyck still cracklesafter more than 70 years. But according to Eddie Muller, originator of the Film Noir Foundation, “The dialogue is a million times better than it is in the book. Cain’s dialogue just sat on the page; it was written for the eye, not the ear.” Writer-director Billy Wilder and co-screenwriter Raymond Chandler took care of that.

On the other hand, when John Huston adapted the prolific W.R. Burnett’s crime novel The Asphalt Jungle for the screen, he took full advantage of Burnett’s words. “He sticks so close to the book, people would be startled,” says Muller. “When Marilyn Monroe calls a cop a banana-head, that’s straight from the book.”

Huston was canny in deciding when to leave well enough alone and when to add or embellish. He made his directing debut with The Maltese Falcon and remained faithful to the source novel … but it was he who had Sam Spade sum up the highly prized “black bird” in a way that author Dashiell Hammett never thought of. With a nod to Shakespeare, he described this unforgettable movie prop as “the stuff dreams are made of.”

That quote has become part of our vernacular and is often used to describe the appeal of movies themselves. That it’s spoken with great feeling by Humphrey Bogart, one of the most famous — and distinctive — voices in all of Hollywood history, certainly doesn’t hurt.