The distortion in this recording makes it hard to understand what he's saying.

distortion 是名词，来自动词 distort（扭曲、变形）。dis- 是表示"否定"或"相反"的前缀，tort 来自拉丁语词根，意思是"扭曲"。distortion 字面意思是"扭曲的状态"，在这里指声音或图像偏离原始状态的变形现象，即"失真"。