General:
* Whisper: This is the most common and direct word for speaking very quietly.
* Murmur: This suggests a low, indistinct sound.
* Mutter: This implies speaking softly and perhaps with a bit of grumbling.
* Hiss: This implies a soft, sibilant sound.
* Coo: This is a soft, gentle sound, often used to describe speaking to a baby.
* Hum: This is a soft, continuous sound made with the voice.
More specific:
* Softly: This is a simple and direct way to describe speaking quietly.
* Gently: This suggests speaking softly and kindly.
* Tenderly: This implies speaking softly and with affection.
* Subdued: This suggests speaking quietly and without much emotion.
* Quietly: This is a general term for speaking without making much noise.
Figurative:
* In a low voice: This is a more formal way to describe speaking softly.
* Under one's breath: This implies speaking so quietly that only the person very close by can hear.
* In a hushed tone: This suggests speaking softly and secretly.
The best word to use depends on the context and the feeling you want to convey.