Every Japanese learner is taught to understand the levels of politeness in speech, and adjust their language according to their conversation partner. However, I have never heard anything about how to speak when in a group setting, when the various people in the group are at different levels in the politeness hierarchy relative to you. Should you speak as though you are 1-on-1 with the person who would get the most polite speech from you? Should you adjust your speech depending on exactly who you are addressing with everything you say? What if you’re speaking to everyone?
To make things more concrete, I once was in a conversation with a close native speaker friend, with whom I speak in casual speech. Then, another native speaker who I didn’t know yet joined, and I decided in the spur of the moment that I should use です・ます forms with her, and continue using casual speech with my friend. I think this worked well, since I didn’t get negative feedback about it, but I didn’t know what to do when saying something that was addressed to both of them at the same time.
I can imagine situations where you would have an even larger gap in politeness between people - say, if you’re at work, talking to your boss and a younger coworker at the same time.
What do natives do in these situations? What would you do? Are there other situations that I didn’t mention that touch on this topic? Do the rules change as the number of people in the group changes?
If you are addressing a group of people and any of those people are someone you would use です/ます with, I would say you should probably use です/ます.
Let’s imagine you went to lunch with a good friend and their mother, who you don’t know.
It would probably work out that you and the mother would use です/ます and the friend would probably not use it. Because for you and the mother, there is someone they need to use です/ます with present. But for the friend, there is no one present who needs to have です/ます added.
If you have something to say specifically to your friend, and it’s clear you are not addressing the mother, then dropping です/ます is normal.
At the same time, there are Japanese people who don’t care about this stuff. I live in Kansai, and it wouldn’t be strange for people to not use です/ます in situations your textbook would say they should. But that’s a cultural difference with other parts of Japan.
This one! In my online calligraphy class, there are a Japanese family (grandmother and two granddaughters). The teacher uses keigo definitely when addressing the grandmother, and ます/です when addressing the rest of us. For the general presentation I think she uses ます/です as well, maybe slightly more formal than when addressing the girls individually.