Since the release of her debut recording, Never Never Land, a mere year and a half ago, 23-year-old vocalist Jane Monheit has been hailed as a sultry, young, white reincarnation of Ella Fitzgerald. With due respect to Monheit, the comparison is neither fair nor accurate. Anyone claiming more than a superficial resemblance between the two would appear to have a limited-very limited-knowledge of singers.

The mature Fitzgerald won our hearts as an improvisational wonder, whether singing blues or bossa novas, deftly reshaping melodies or abandoning them for incredible wordless excursions. From a technical and historical standpoint, she stretched jazz singing from the swing era into the realm of bebop. No small achievement, but second to the visceral thrill of her creations. Fitzgerald made us feel like we were airborne: her take-offs, landings and the surprises that lay in between made the human voice appear boundless. It was simply magic.

Though an accomplished young singer, Monheit does not possess Fitzgerald’s penchant for invention. On Come Dream With Me, her latest recording, she only strays from the original melodies occasionally and self-consciously at that. Her variations on the Billy Strayhorn classic “Something to Live For” suggest a dearth of harmonic understanding; the song, in general, requires sophistication that is beyond her. “I’m Through With Love” shows Fitzgerald’s influence in certain decorative flourishes, yet these additions feel superfluous. Like many others, Monheit fares better with an economy of style. Streamlining aids her expression instead of curtailing it.

Her lack of improvisational savvy should not bother us much-at least in principle. It is possible to be a great singer-if not successor to the “First Lady of Song” -without that particular attribute. But Monheit is missing other, more essential ingredients in the Fitzgerald antigravity formula, ones that nonimprovising greats like Frank Sinatra and Rosemary Clooney also share: infallible rhythm and spontaneity in delivering lyrics. Upon close inspection, they render the Monheit/Fitzgerald comparison null and void.

Sure, she can breeze through an easy, medium-tempo swinger like “Hit the Road to Dreamland”-so can dozens of other singers-but her internal clock proves less convincing on the album’s many ballads. “I’ll Be Seeing You” comes to mind with its awkwardly anticipated phrases: she sings as if her lover might really be around the next corner, contradicting her own mournfully nostalgic tone. She has never recorded anything that qualifies as uptempo, the closest being Jobim’s “Waters of March” and a poky version of “Twisted” on Never Never Land. For all the talk about her sexiness, the word that often qualifies her comparison with Fitzgerald, her sense of time seems oddly distanced from her physicality.

Her lyric interpretations are similarly predictable and narrow. Monheit pulls away on the syllable “where” in “Somewhere Over the Rainbow” for a marvelously wistful effect a la Judy Garland-but that mannerism pervades her ballad work. She withdraws from the highest notes of each phrase and never once sings at full voice in her upper register. Although they may be beautifully polished, her lines inevitably fall into the same arclike shape. She reaches peaks, but never builds enough velocity to overcome gravity.

Monheit’s rehearsed, theatrical quality has less in common with jazz musicians than torch singers, cabaret artists and those who sing musical theater. Perhaps that’s where she belongs, in the Oak Room or the cast of Carousel, her pouting lips pressed into service for chorus upon chorus of “That Was a Real Nice Clambake.” Her pretty, ultrafeminine image, one that seems dated and in keeping with the tame, passive way she approaches her repertory, probably appeals to the silver-haired folks who frequent such establishments. Unfortunately, it fails to attract those of us with more adventurous and, ironically, younger tastes-like Fitzgerald, for one.