Chrissellene Petropoulos is a soprano. But listen to her talk, not sing, and suddenly she is an oak tree, or a package, or a cake or a sponge -- metaphorically speaking.

"There are just so many people who have helped in the building of this tree -- this oak tree," she says, referring to herself. "So many people have influenced it: They all watered it, fed it, made sure it had sunlight, made sure it didn't go crooked, turned it . . .

"The unveiling of the oak tree is my recital on Wednesday -- after 12 years of growing. The tree wants to come right out and say, 'Now, you all sit back and let me show you what you have done for me.' That's what this recital is for."

Petropoulos, a native Washingtonian, is 32 years old. It is her voice that has been 12 years growing as a musical instrument. At age 4 she started on the piano. Thereafter she dallied with any instrument she could get her hands on: violin, recorder, guitar, viola, cello . . . until finally she discovered her me'tier: singing. Her Kennedy Center recital debut is at 7:30 p.m. Wednesday in the Terrace Theater.

When Petropoulos isn't being an oak tree, she is a package -- carefully filled with years of nurture and education: "All the ingredients are in this package, and it is now, TAA! DAA! -- 12 years ready. That package has a little hole -- at the top -- that will always get more and more in it, that will never be filled."

Then, for a minute, she's a cake: "The basic ingredients of the cake are in there," says Petropoulos. Her personality, unrestrained, is so vibrant and mirthful that it taxes the imagination to picture her, dressed in a formal gown, her long dark hair gathered atop her head, singing a recital of songs by Bellini, Mozart and Poulenc.

What Petropoulos' training has added to those basic ingredients is impressive. She has garnered enthusiastic reviews, locally and abroad, that laud her as "a seasoned and versatile artist," whose singing combines "musicality and vivid expression."

"The only credit I will take," says Petropoulos, "is that I work hard." The number of people she does credit could easily fill the 500-seat Terrace Theater. "Everybody knows what a tree looks like. What's interesting is how it got there." With that she's off and running, tearing through the list of names that "got her here": her coach Sina Berlinski, her voice teachers, her parents, her accompanist Vladimir Sokoloff, Doug Wheeler and the Washington Performing Arts Society ("They're the ones who asked me to do this recital") . . .

Modesty aside, what about ego? "I am just not interested in Chrissellene's ego. She's got a husband and parents to take care of that side," she says, seated in the living room of her parents' Potomac home -- where tables are strewn with photos of the Petropoulos' only child and with laminated clippings of her reviews and profiles.

"I don't sing for stardom, for money or for an ego trip. I am a mere slave of communication to the people for the composer. When I step out on the stage, Chrissellene is nowhere to be found. She clicks off. I have a whole bunch of buttons. One is Strauss. One is Mozart. One is Bellini . . . On stage, you respect the composer more than yourself. Leave Chrissellene and Cuckoosville and personality back there," she says, dismissing herself with a sweep of an arm.

Petropoulos began college expecting to become a music therapist. Singing professionally wasn't even a consideration; but when the decision was made, she followed a steady course: a BA in music from the University of Maryland, postgraduate work at the Curtis Institute of Music in Philadelphia and at Indiana University, and then Europe.

Europe was a must. Petropoulos spent four years there -- in Italy, Greece, France, Austria and Germany -- immersing herself in music. "I was a sponge . . . I wanted those languages and the culture! I wanted to know what it's all about."

Her two years with the Vienna State Opera bear more resemblance to the ordeal of a medical intern than to that of an artist cultivating her talent. "You eat, drink, sleep, think, breathe music. All day long you rehearse. All night long you perform. Seven days a week you're on call. Every night, every other night, five nights a week . . . you are out there on stage, doing something. You've got all these roles in your head, that's the repertoire for the year, and you've been chosen for that repertoire . . . It didn't matter if you were half-dead: the show went on! Unless I had a sore throat, I performed."

When her contract with the Vienna State Opera expired in 1984, Petropolous came back home. "I felt I had sponged up everything a singer should have in her package. She must have all this. She must be cultured, languaged, coached, shoved, kicked, cheated on . . . the whole nine yards. You've gotta have it all to get out there. But I wanted to do it in my own country, where I was born. Not in Europe."

She is as loyal to her home town as she is to the people who have helped her. "My dreams, my spirit, my backbone . . . everything is in Washington. Wherever it goes is fine, but I want it to start right here. I want to make people proud -- these people who have believed in me."

Petropoulos eschews the attitude that a New York base is a precondition for an artist. "I don't understand. Am I going to sing any differently with a New York address? 'You're recognized,' people say. 'We'll take a look at you when you live in New York.' Well, let me tell you, I am going to have to change that. There are capable, wonderful artists here . . ."

Any last words? "Just say, 'Chrissellene Petropoulos is a singer.' Then write, 'Thanks, thanks, thanks, thanks . . .' all down the page."