VOA一分钟英语：三种不一样的 “轻声说”： whisper, murmur, mumble

“Whisper、murmur” 和 “mumble” 作动词时都可以表示 “小声地说”，它们之间的区别是什么？哪个词的意思是 “刻意压低声音，只让身边的人听见”？想要说一个人 “小声嘟囔”，应该用哪个词？
 
I’m Georgina from BBC Learning English. Do you ever wonder about the difference between whisper, murmur and mumble? They are all used to describe different ways of speaking quietly.
Whisper means to speak quietly, often on purpose, so that only someone very close can hear what you’re saying!
I don’t want everyone to hear! I’ll have to whisper.
I’ve got a secret to tell you. I’ll have to whisper it though.
Murmur means to speak quietly, often in a low continuous voice, so it’s hard to understand.
‘I love you’, she murmured in her sleep.
“Do you want to go for a coffee?”
I can’t understand what you’re saying. Stop murmuring!
Mumble means to speak quietly, often in a low voice, making it difficult to understand.
She’s always mumbling and complaining very quietly, so I can’t hear! It drives me mad!
“I’m really sorry. I shouldn’t have eaten the last biscuit!”
That was a really mumbled apology, I could hardly hear it!
Bye!
 
用法总结
1 “Whisper” 用来表示 “因为只想让身边的人听到，所以故意小声说话”，类似于汉语里的 “说悄悄话”。
I don’t want everyone to hear! I’ll have to whisper.
I couldn’t hear what the children were whispering about.
 
2 “Murmur” 用来表示 “持续地低声说，低语”。
‘I love you’, she murmured in her sleep.
He was murmuring continuously.
 
3 “Mumble” 用来表示 “小声嘟囔”。
She’s always mumbling and complaining very quietly, so I can’t hear! It drives me mad!
I couldn’t understand what he was mumbling about.