Question about switching formality in a conversation


In case I am talking with someone using the informal form but we are not close
friends yet (perhaps a close acquaintance or someone I'm chatting with online)
and I want to ask him a personal question (what is his occupation, something
about his family ,etc.), should I proceed with the informal form or should I
switch to polite (or even honorific) language to ask him the question?




This heavily depends on your character, your age, the relationship between you
and him, and how personal the information you're trying to get is. In general,
using honorific forms is probably an overkill, but temporarily switching to
the です/ます style will not harm.

Personally, I am relatively slow to start dropping です/ます, and I am unlikely to
talk with someone using the informal language if I don't even know his
occupation.




It's not that uncommon to be talking simultaneously to two or more people
using different levels of familiarity/politeness, but for the same person,
using the same level throughout a conversation is the norm.

Switching between levels of formality/humility in the same conversation with
the same person is just not necessary. Even if the kinds of things you wish to
talk about change from "general" to "personal", whatever form of speech the
two of you began with, you can continue with. That said, if you choose to
switch to using the polite "masu" form of verbs rather than the root form, I
don't think that's bad. Your conversation partner might misunderstand and
think that you suddenly feel less comfortable with them, but I doubt any real
conflicts will occur.

I have always had a problem with "keigo". I get easily confused by humble vs
polite vs honorific speech... though I have been told over and over that as a
foreigner, it is fine to simply use the polite form with everyone all the
time, until you consider them to be close friends (and as long as you are
outside of work... at work always use polite speech... a rule I break far too
often, but get away with because my schools are very kind....)

There have been times when I switch back and forth between levels of
politeness, and as a foreigner these are either ignored as "he just doesn't
know" situations, or it gets a small laugh or a humorous comment.

doing a google search for "when to use keigo" might lead you to useful
websites.

