loud和loudly作副词的区别是用法、搭配、读音和侧重点不同。
区别：
1、用法不同。
（1）loud指声音响亮，高声说话，一般放在所修饰的动词后面。
（2）loudly与loud含义相同，可放在动词之前或之后，用以说明声音的强度，含“喧闹”的意味。
2、搭配不一样。
（1）loud 主要与talk、speak、sing、laugh等连用。
（2）loudly则可与任何发出声响的动词如bring、explode、 knock 和insist、demand、explain等连用。
3、读音不同。
（1）loud的英式读法是[laʊd]；美式读法是[laʊd]。
（2）loudly的英式读法是[laʊdli]；美式读法是[laʊdli]。
4、侧重点不同。
（1）loud侧重状态和给人的感觉。
（2）loudly则侧重方式。
loud和loudly的例句：
1、I heard a loud bang and then saw black smoke.
我听到一声巨响，然后看到黑烟。
2、A treacherous court official that cheats a monarch is like a floating cloud obscuring the sun.
奸臣当道犹如浮云蔽日。
3、The abdomen that the cloud just detects when having a meal is a little protuberant, feel embarrassed however inquiry.
吃饭时才发觉云的腹部有些突起，却不好意思询问。
4、The brothers laughed loudly at this and shouted: "Come on, down to the shed!"
他的兄弟们听到这句话就开始大声的欢笑并叫嚷着：“走吧，到棚屋去！”
5、People were chatting loudly or speaking on cell phone so you can hardly read," Chen said.
“人们大声聊天或用手机通话，所以你很难阅读。”陈说。
6、Nicky likes to play peek-a-boo, hide and seek, and scream loudly to tell how much he likes to play.
天天喜欢玩藏猫猫，经常高兴地尖叫，耳朵都要被他给震聋了。