whisper — to speak with soft, hushed sounds, using the breath, lips, etc., but with no vibration of the vocal cords.
murmur — a low, continuous sound, as of a brook, the wind, or trees, or of low, indistinct voices.
hiss — to make or emit a sharp sound like that of the letter s prolonged, as a snake does, or as steam does when forced under pressure through a small opening.
