The pauses and stammers, the thoughts that roll over each other, the skittery spirit of disconnection for those, like me, who admire the films of John Cassavetes in theory but weary of them in execution, the trouble with his shaggy improv style is that it's realism italicized, made overstated in its understatement. But time or conversation, at least may finally have caught up with him. Andrew Bujalski's Funny Ha Ha, an ebullient sliver of a movie, follows a group of men and women in their early 20s, and for once the un-dialogue dialogue doesn't come off as an affectation. It's the sound of the Tentative Generation slackers who stutter to look cute, then use a phrase like ''Got it!'' as a weapon. Marnie (Kate Dollenmayer), smart but careerless, with a sensual curl to her lips, is caught between her desire for love and her girlish compulsion to show no aggression whatsoever. She's trapped in an abstract bohemia of the brain, and Dollenmayer makes her fumbling fragmentation a thing of awkward beauty.