I read it's different that's because when you hear your own voice, it hasn't escaped the nasal cavity yet, so everyone's voice sounds more nasal in reality than it does in their head. People often say they hate how their voice sounds to other people. However, before recording technology, I don't think people had any way to hear their own voice (maybe echoes?). Did people understand they sounded different to other people in theory, even if they had never heard an example?