As a self-proclaimed ''all-American Jewish lesbian folksinger,'' you'd think Phranc would have a wealth of experience as an outsider to write from. Think again. The L.A.-based Phranc pens ironic little ditties, high on giggles but low on the insights that should come out of a lesbian's daily life in the straight world. On her third album, Positively Phranc her songs are still too thin to bear repeated listenings. Typical is ''Hitchcock,'' a funny song about Phranc's obsession with a woman who looks like Kim Novak in Alfred Hitchcock's film Vertigo. Too bad the result is so dismissably cute that the song's confident lesbianism becomes compromised. This is a particular shame because Phranc is not only one of the few openly gay performers on a prominent record label, but also one of fewer still who, when writing about romantic attraction, directly mention the gender they're hot for. Phranc's deficiencies can't obscure her lovely voice or her way with a melody. But if she doesn't put more meat in her writing, she'll continue reducing her point of view too rarely reflected in pop-to a mere novelty.