David Mamet has made his name as one of the most aggressive talents in contemporary American theater by pioneering a profane form of the vernacular, dubbed "Mametese."

At his most dextrous and incendiary, in plays like "Glengarry Glen Ross" and "American Buffalo," his characters compress street talk into verbal bullets.Yet the pace of Mamet's work isn't just rat-a-tat-tat. Part of his cunning lies in the whirling variety of his attacks and reversals. Actor Joe Mantegna's opening speech in Mamet's "Glengarry Glen Ross," in which he lays out his entire philosophy before you realize that he's a salesman pitching to a mark, made Mantegna a Broadway star.

As the writer-director of the movies "House of Games" (1987) and the current "Things Change" with Don Ameche and Mantegna, Mamet has added another weapon to his writing arsenal: silence.

"All the moments you really remember in movies are silent moments," he said during an interview.

"The exchange of looks between Donna Reed and James Stewart at the dance in `It's a Wonderful Life,' or between Warren Beatty and Julie Christie in the underpass in `Heaven Can Wait.' The underpass scene in `Things Change' pays homage to that."

The choice of those two movies tells you something unexpected about Mamet, who won a Pulitzer Prize for writing rabidly about real-estate salesmen playing hardball in "Glengarry Glen Ross": Mamet has a soft spot for heart-tugging film comedies, even when they're as sentimental about youth and age as "Cocoon" and "Big."

That makes it less surprising that his second movie would be a funny, poignant fantasy about a Mafia wise guy who's not as smart as he thinks, and an 80-year-old shoeshine man (Ameche) who's mistaken for a mob boss (and inadvertently passes some of his wisdom along to his buddy).

In an unpretentious way, Mamet is a movie buff. "When Shel Silverstein and I wrote `Things Change,"' he said, "we thought about the great Italian comedies like `Big Deal on Madonna Street' and `Bellissima' - movies that are wonderfully dry. Also, mistaken-identity movies like `The Prisoner of Zenda,' and `Moon Over Parador' (of course we hadn't seen that one) and Robert Heinlein's novel `Double Star,' a book about an actor who impersonates a Martian that I read as a kid.

Mamet doesn't as a rule direct his stage scripts. But he's quickly grown to love directing his own movie scripts: "The thing about making movies is that it's a gang comedy in itself."

Even though he doesn't separate his movie from his stage work ("I want to be able to do both. You know the saying: `A change is as good as rest' ") he speaks more light-heartedly about films in general and his own movie work. "House of Games" and "Things Change" are full of tricks because "tricks are basically the things I like."

The sardonic, deadpan humor that leavens these films comes easily to Mamet. One of his other best friends is stand-up comic Jonathan Katz, who co-wrote the original story for "House of Games" and appears in "Things Change" as a Tahoe resort comedian.

Mamet uses a game he plays with Katz to explain the real reason for the spare storytelling that some have called "minimalism" (a label that Mamet himself says "never seemed apposite to me"): "I see myself as a comedian by nature. Me and Jonathan Katz play a game - to tell a joke and have the other guy try to beat you to the punch line. The guy who gets egg on his face loses; between me and Katz it comes out about 50-50. Basically, I don't want anyone to beat me to the punchline. I'll throw anything out in order to avoid that."

But Mamet is also a born melodramatist who believes in the concepts of honor that Elliot Ness mouthed so unconvincingly in his script to "The Untouchables." The rasping cynicism that permeates "Glengarry Glen Ross" and his tale of Hollywood, "Speed-the-Plow," expresses the response of a ravaged idealist to the everyday corruption of the world.

Mamet agrees that the turning point in "Things Change" comes when Gino initially turns down the Mob boss' offer and is subsequently ignored by the don and silently rebuked by the don's consort: "The don is saying he's not a man of honor, the girl is saying he's not a man!"

When it comes to moviemaking, Mamet prizes directness and honesty. That's one reason he treasures his co-stars in "Things Change": "Both Ameche and Mantegna are unswerving in their perceptiveness and clarity. They're not overly involved in their own emotionality. They give you the sense, `What I may be feeling is my own business. I want to express what is in the piece.' "

Mamet's favorite directors include John Ford, Frank Capra, Preston Sturges, Josef von Sternberg, Jean Renoir, Luchino Visconti and Akira Kurosawa ("There's never been a better movie made than `Ikiru'!").

Old movies have served as Mamet's film school: "I have so much to learn. And there's a lot to learn from stuff that looks the simplest, like the look of `Young Mr. Lincoln,' the structure of `The Great McGinty.' "

He's constantly using the works of the old masters as reference points. Asked whether he intended the Ameche character to resemble the Peter Sellers character in "Being There," Mamet said, "The Sellers character was more of an idiot savant than an innocent. I think the heart of the movie is more like Kurosawa's `Dersu Uzala,' the relationship between the worldly Soviet explorer and the innocent peasant guide Dersu."

But Mamet doesn't have any game plan to recapitulate film history in his career. And his next film, "Homicide" (based on William J. Caunitz's novel "Suspects," and starring Mantegna), will be a rough, nasty police story.

Mamet doesn't pretend to know why he chooses his projects: "Why does a beaver make dams? Because if he didn't gnaw trees his teeth would get too long. So the beaver gnaws trees. Let the chips fall where they may."

Thinking of life beyond movies, Mamet said, "I like beavers. We sit there in Vermont, in our backyard, and watch the beavers. And," he said with a theater artist's special satisfaction, "the beavers watch us."