Well, it depends on the particular teacher, of course. Not to mention the particular students. But my writing workshops are essentially reading classes, though we're reading in a particular way. We read as writers, with a mind to determining how the writer has achieved the effects she's achieved, so that we can then imitate what we admire and eschew what we don't admire. For me, a writing class (whether we're discussing a student story or published work) is a prolonged act of hyper-self-conscious reading. We learn how to recognize consciously what we previously experienced only subconsciously. We become self-conscious about language, about punctuation, about everything, to the point sometimes of near-paralysis--all in the name of learning how to do it ourselves as writers, at becoming so adept at it that we are able to take that subconscious matter made conscious and place it back into the subconscious again. That way, we proceed intuitively, but only once we've rewired our intuitions.
Take Tim O'Brien, who strikes me as among the best of contemporary writers at varying his sentence cadences and at using the sound of language and the architecture of his sentences to evoke a particular mood. I talked about this some last year in my first guest-post go around with respect to Jayne Anne Phillips's story "Fast Lanes." Take a look now at this passage from early in O'Brien's story "The Things They Carried." Jimmy Cross, leading his battalion in Vietnam, thinks of Martha, a college junior back in New Jersey, who writes Jimmy letters but who doesn't reciprocate his love for her:
"A dark theater, he remembered, and the movie was Bonnie and Clyde, and Martha wore a tweed skirt, and during the final scene, when he touched her knee, she turned and looked at him in a sad, sober way that made him pull his hand back, but he would always remember the feel of the tweed skirt and the knee beneath it, and the sound of gunfire that killed Bonnie and Clyde, how embarrassing it was, how slow and oppressive."
Try reading that sentence aloud. I believe all writers should read their work aloud; it enables them to hear things. It's a long sentence, certainly, but more important, it's breathless: all those "ands," those short, choppy clauses followed by a much longer clause, before the clip gets more restrictive again. It's this breathlessness that's essential, because it mimics and evokes Jimmy Cross's own breathlessness as he places his hand on Martha's knee--mimics, too, what's happening on the screen, the gunfire, the staccato rhythm of that. Reading this sentence, I'm reminded of what a writing professor of mine once said: "Given the choice between the word with the right meaning and the word with the right sound, you should choose the word with the right sound."