Other forms: mellifluously
Use the adjective mellifluous to describe something that sounds sweet and smooth, like the honeyed voice of a late-night radio DJ.
You might think that the mell in mellifluous has something to do with mellow, but it actually comes from the Greek word meli, meaning "honey." The word is related to the mythological nymph Melissa, whose name means "honeybee." Melissa is said to have discovered that the smooth, sweet stuff that honeybees produce is edible. The word mellifluous combines meli with the Greek root fluere, meaning "to flow," so that something that is mellifluous sounds as if it is flowing like honey.