pleasing to take in: sweet on the tongue or lovely to the ear, named for the pleasure it gives the one receiving it
This word describes something from the receiver's side. It does not name a flavor or a tone of voice; it says that whatever is being tasted or heard goes down well with the person taking it in. That is why one small word can cover both a mouthful of bread and the sound of someone speaking.
Both of its appearances turn on that pleasure. In Proverbs, food got by cheating tastes good at first, and the saying grants that for half a line before pulling the rug out: the same mouth ends up full of grit. In the Song of Songs a man asks the woman to speak because her voice is a delight to him, and the line sets that pleasure beside the loveliness of her face.
The closely related verb is used far more often, of sleep that comes easily, of a longing finally satisfied, and of an offering that God finds acceptable. Keeping that wider family in view helps, because the thread running through all of it is that something is welcome to whoever receives it. Hebrew has near neighbors that stop short of the same thing, such as מָתוֹק, which names sweetness as a flavor, and נָעִים, which names loveliness or charm in a much broader way.