Teri Garr has come a long way since her first speaking role, in the movie "Head"; just bitten by a snake, she exclaims, "Quick, suck it before the venom reaches my heart."

Actually, she says, "there was another great line: 'I and Velma ain't dumb.' "

Then, of course, there is Sandy Lester, the stepped-on girlfriend of Dustin Hoffman she plays in "Tootsie." Her favorite line here: "I had a wonderful time. My date left with somebody else. Do you have any Seconal?"

"I was at Bullock's the other day," Garr says, "and I heard this one woman telling another woman, 'I invited this guy over to my house. I made him a coffeecake and he never showed up.' I thought, Hey, you jerk. I just played you in a movie! I guess I really know all these women that I play, the doormats of the world. But I'm not them at all."

She pauses.

"I'm really not, am I? You don't think of me as the dumb little housewife, do you?"

It's this insecurity that may make Teri Garr so appealing, so wonderful, so real on film. She is at once a very competent actress, a quick raconteur and, in the words of Pauline Kael, "the funniest neurotic dizzy dame on the screen."

Movie stars of old, such as Katharine Hepburn and Grace Kelly, were admired because they played roles larger than life and seemed to personify an ideal that couldn't be achieved by ordinary mortals. Modern realism has brought a new esthetic: the movie star as ordinary person. Paul Newman as a drunk, Burt Reynolds as a would-be father and Teri Garr as . . .

Not quite the girl next door; that would be too perfect. She's more like the girl next door to the girl next door. In most of her roles, she's managed to conjure a woman of her times, the Diane Keaton of "Annie Hall" on a more realistic level. Whereas most men her age would say, "I'd love to date Diane Keaton," most men Garr's age would say, "I have dated Teri Garr."

Now, the only problem with this equation is that Teri Garr is not saying how old she is. "Somewhere between 30 and 40," she offers. "I was auditioning for 'Sweet Charity' and Bob Fosse asked me how old I was and I told him. And he said, 'I'll give you one piece of advice in this business. Never tell anyone how old you are.' By the way, I didn't get the part."

There have been plenty of other parts, though. Gene Hackman's girlfriend in Francis Coppola's "The Conversation" ("I was locked in a room. I couldn't get out. Francis said to me, 'This has always been my fantasy, to have a girl locked in a room who would be there when I wanted her.' "); Richard Dreyfuss' wife in "Close Encounters of the Third Kind"; John Denver's wife in "Oh, God!"; Raoul Julia's girlfriend in "The Escape Artist"; Gene Wilder's lab assistant in "Young Frankenstein"; a con artist in "Sting II" ("I still don't know what that film is all about," she says); and, as she puts it, "the horse's stepmother" in "The Black Stallion" and "The Black Stallion Returns."

"I had done all this work on the first film to give the mother more character," she says. "I wanted her to be a real strong woman of the '40s, a widow but real tough, a piano teacher. I even sang 'Chattanooga Choo Choo.' At one point Francis Coppola, who produced the film called me over and said, 'Teri, this is a story about a boy and a horse. It's not about his mother.' I loved that woman I created and she wound up on the cutting room floor.

"See, my own mother was like the woman I was trying to portray. My father died when I was 11. He was a vaudeville comedian. He worked in one movie, 'Ladies of the Chorus,' as Marilyn Monroe's father. My mother was a Rockette at Radio City. I have two older brothers; one is a doctor, the other sells boats. My mother was a real tough cookie. She raised the three of us and she worked at the same time."

Garr was born in Hollywood, but grew up in Franklin Lakes, N.J., where the family moved so her father could work the vaudeville circuit. They returned to Hollywood when her father got his movie part. "I went to North Hollywood High. I'm the original Val girl."

She started dancing at age 7; 10 years later she was a hoofer in Elvis Presley movies and working on the TV show "Shindig." "It dawned on me that I was better than the people dancing in the row in front of me. But sometimes it's hard to be assertive. Even now, when I get tired of playing the roles I do, I think of the million other women who want to be me and I go right back to work and say, 'Thank you very much.' "

Garr studied ballet formally, including some time with George Balanchine. "Basically, though, what you learned was how Pavlova did her hair and how to eat ballet food. Ugh! She scrunches up her face. My big problem was that I loved to eat. I still love to eat."

Right now she is munching on dried apricots, which had been stored in the refrigerator of her Hollywood Hills home, where she lives with her boyfriend, Roger Birnbaum, a producer. "My idea of cooking," she says, "is doing the dishes.

"But I've always loved to dance and act. I was in the touring company of 'West Side Story' and I always had this American pie face that would get work in commercials: Crest toothpaste an old magazine ad is hanging on the wall , Folger coffee, Joy, Tide, Cheer. I even played Chiquita Banana, and I'd say things like, 'Hi Marge, how's your laundry?' or 'Hi, I'm a real nice Georgia peach.' Sometimes this work is one step above being a cocktail waitress. Once I played Cher's dog on TV."

Life, however, hasn't turned out so tough. Garr drives a silver 450SL Mercedes now, and in swank restaurants, without a beat, orders Sankaccino. She has an apartment on 11th Street in New York City, where she'll have a stage role after finishing her latest film.

Earlier in the day, Garr had wrapped up a TV interview, one of scores of interviews that had been orchestrated, theoretically, to improve her chances of winning the Academy Award Monday for her role in "Tootsie." Ironically, her biggest competition is Jessica Lange, who also has been nominated for best supporting actress for her role in "Tootsie." If Lange were to win, life would in a sense imitate art, with Garr once again losing out to Lange, as she does in the movie.

"It wouldn't really be like that," Garr says, "I mean, I like Jessica a lot. She's a friend. This Academy Award business is a little crazy. It's like one high school voting against another high school. I know it means something at the box office but . . . So what. It's sort of like this house. This house was built as a set for a movie. Sometimes I say to myself, It's not real."

Most recently Garr has been making a new movie, "Mr. Mom," with Michael Keaton and Martin Mull. Keaton has been laid off as an automobile executive in Detroit and Garr, drawing on her cooking skills, becomes the family breadwinner as the head of a tuna fish canning company: "Schooner Tuna--The Tuna With A Heart."

"I tried to make the character a little more real," she says, "and they stopped me dead in my tracks. You don't have to have too much of a brain in this business to realize that the only way you'll ever get to do anything that you really want to do is to become a director. That's why all of us were so excited at Zoetrope Coppola's studio . Francis was telling all of us that we'd be writing movies, directing them. I didn't know for years what a clapboard was for. But even the janitors were going to have their own offices. It was a great idea but I still haven't been paid for 'One From the Heart,' my only starring role. Maybe 10,000 people saw me in that one. Well, at least I got to do the tango up on the screen. I love the tango!"

And with this, Teri Garr gets up in her kitchen and begins to dance.