M dp has a friend who visits sometimes after moving away some months ago to live in the region where they spent the first few years of their childhood.
I noticed that when they arrived to visit, we had a full conversation together and they spoke the same as they ever did, before the move.
Then a couple of hours later we were out in a restaurant and when speaking to the staff, the friend's accent changed entirely, taking on a different lilt and pronouncing words completely differently. The new accent didn't match that of the people running the restaurant either, who were from a different region to all of us.
After the meal, and for the rest of the visit, speaking to others etc the new accent didn't reappear again once.
We didn't say anything in the restaurant to the friend, but I mentioned it to dp afterwards. I thought the accent change seemed odd, especially as it didn't last long and never reappeared that weekend. Dp agreed they'd not heard that accent before from them, but suggested it could be something that happens naturally to people sometimes. I'm curious about it, and wondered what caused it and if it would be terribly rude to point it out if it happens again. I felt weird that neither of us mentioned it at the time, it was such a change.
I'm aware of code switching which makes sense to me and I find myself doing it sometimes myself, but it's not really a conscious thing and not a change to an entirely different regional accent.
This was more like switching from their regular Leeds accent to a Somerset one and then back to Leeds for the rest of the time.
What do you think caused it?
YABU, it's perfectly normal in these circumstances
YANBU, it's odd