Comment by bccdee

Yeah—I'm reminded of the opening sentence of Slaughterhouse Five, which goes, "Listen: Billy Pilgrim has come unstuck in time." Kurt Vonnegut isn't worried that you're not listening; he's trying to create a sense of intimacy and emphasis, as one who is taking you aside to tell you something crucially important which he fears you may dismiss out of hand.

It seems intuitive to me that the "hwaet" functioned more as a literary device than as a simple call for attention. It is, after all, a poem.