In a word: susurrant

Example: From James Parker's 2011 article in The Atlantic on R.E.M., "America's Rock Band": "When challenged in the early days about his sleepy, susurrant diction and bric-a-brac phraseology, or about the lack of a lyric sheet inside R.E.M.’s records, Stipe would sometimes refer questioners to Walker Percy’s essay 'Metaphor as Mistake'—an exploration of the ways whereby (as Percy writes) 'misnamings, misunderstandings, or misrememberings' can lead to 'an authentic poetic experience … an experience, moreover, which was notably absent before the mistake was made.' ”