translation.en: What I'm going to do now is just play some examples of real human beings laughing, and I want you think about the sound people make and how odd that can be, and in fact how primitive laughter is as a sound.
translation.zh: 现在，我会播放一些真人发笑的片段， 大家来听听那些人的声音， 想想它们有多奇怪， 以及笑声实际上是一个种多么原始的声音。