@Blackcloud just read about your experience on the train 2 weeks ago (yep, still that far behind myself 😅). It does sound odd. But... i wknder if she possibly wasn't speaking to/about you, but rather to herself? 🤔 i wonder if she was staring and/or trying to make eye contact?
If she was trying to talk to you for that long, I reckon she would notice you didnt hear (or understand) and they would stop 😊.
A number of times in my life i have observed people speaking to themselves in public. And often people who are loud and in distress (sad, angry, paranoid... can be different types).
When I'm alone sometime I talk to myself in the 3rd person too! 😅🤣. Yeah, i know I'm weird. But i do it very quietly as my own way of processing thoughts or what i need to do. Its the same as when i talk to my dogs - except my dogs arent there to talk to 🤣.
Rest assured i don't do it at a volume others would hear though! And i definitely wouldnt be staring at a person while doing it either.
Its one of those things that probably will "never be known" what happened. But in case it still plays on your mind, i thought i'd offer up an alternative possibility that came to mind from my own experiences 😊.