Inaudibly tells you HOW something is said or done: too quietly for others to hear. Someone may answer inaudibly into their chest; a name may be spoken inaudibly at the back of a room. The words leave the mouth, but they do not arrive as something the listener can catch. It is the adverb of inaudible, so it goes with a verb: whispered inaudibly, sighed inaudibly, muttered inaudibly. It does not mean the person had nothing to say, and it does not mean the idea was difficult. It only means the sound was too small. You will see it in stories more than you will hear friends use it. Though actually, writers sometimes use it for things that are not speech at all — a door closing inaudibly, a step taken inaudibly — meaning the noise was there in theory but nobody caught it. In speech, people more often say “too quietly to hear” or “I didn’t catch that.”

聽不見地