Rebecca Parris has performed jazz for nearly two decades, having produced  over ten CDs.  Admired by vocal icons Shirley Horn and Sarah Vaughan,  Rebecca is known for her ability to convey a song's underlying emotion  through masterful phrasing and the infusion of feeling.  She has an  inherent sense of swing and musical structure, lending authenticity to her  improvisations.  You cannot listen to Parris for more than a few moments without being  startled by her talent - startled by the range and subtlety and power of  her voice. "I hear a little Carmen McRae when I listen to Rebecca," says  Ron DellaChiesa, the jazz disk jockey at WGBH in Boston. "And a little  Sarah Vaughan. I think she's on that level. Her phrasing is what is most  extraordinary. She never sings a song the same way twice in a row." The  fact is, Parris is a practitioner - a guardian, one might say - of an art  form that is becoming scarce; an artist preserving a great American  tradition more for its own sake than for her own glory or profit.