降低声音英语是reduce the sound。
相关短语：
1、放低声音lower one’s voice.
2、压低声音lower one's voice.
3、压低声音；使缓和keeo down.
4、把声音降低keeone's voice down.
5、降低我的声音turning down my voice.
6、低声in a low voice;under[below]one's breath.
7、降低说话的声音sink one's voice.
8、降低reduce;cut down;abate.
9、超低声infra-audible sound.
10、低声的in a low voice.
例句：
1、Mrs.fisher added in an undertone to selden.
费雪太太小声对赛尔登说。
2、Hush,boys,the party's getting noisy.
小声点，孩子们，你们太闹了。
3、Some of them began to protest faintly.
其中也有一些人开始小声抱怨起来。
4、At first he cried softly to himself.
他先是小声暗自啜泣。
5、He spoke a harsh,bitter word under his breath.
他小声地说了句不客气的挖苦话。
6、Linda,turn down the record player.i'm trying to read.
琳达，把电唱机关小声点，我想看书。
7、"will they attack?"whispered an awed voice.
“他们会攻击我们吗？”一个人战战兢兢地小声问。
8、Keep your voice low.
你要小声说话。
9、I am afraid,nelly,i shall lose my labour,he muttered to me.
耐莉，恐怕我要白费劲了，他小声对我说。
10、Pickering whispers to eliza and points out the ladies'room.
辟克林对伊莉莎小声说话，指给她女客衣帽间。