How do Japanese speakers transition from polite to plain form amongst friends?


When you first meet somebody, polite language is, on the whole, the most
commonly used form of Japanese. Children may differ, and I understand that not
_everyone_ will use plain form, but regardless a majority of people do.

At some point in a friendship, inevitably friends will switch to plain form.
Again, different people are comfortable to do this at different times, but
**how do people make the transition from polite to plain language?** Do they
just start using it, and the other person just plays along? Is it a gradual
thing, where you switch in and out of plain form and then just stick to it
after a while after using it more and more?

Personal experiences and examples are welcomed




In my experience, the nature of the relationship and the nature of the
communication are both important for knowing when/how to use the plain form
and to knowing what the use of plain form signals.

In **written** _workplace_ communication, I never see plain form (I work at a
university).

In **written** _personal_ communications (things like Facebook or IM), I
rarely see ~ます forms. Only in the most formal invitations do these crop up.

In **verbal** _workplace_ communication, I've seen quite large variance among
language users. Some users almost invariably use the polite forms; other users
use plain form except when giving a formal communication (e.g., say starting a
meeting or being the person who is handling the meeting point). One parameter
that affects this is the role/position one has in the organization and
meeting.

Consequently, I am much more careful to use polite forms in 運営委員会 than when I
am talking to my own students. Though note, that the use of polite / plain is
almost universally mixed in the communication I encounter. Some professors
insist on polite forms from their students and use 僕 to refer themselves;
others don't care whether students give them polite forms or not.

My advisor when I came to Japan generally used the plain form when talking to
me, but the first sentence was often in a polite form. I generally but not
universally use the plain form when talking to my students. Some professors
(who sound refined when they do it well) stick to the polite form for almost
all communications in person.

In verbal communication among friends, I would say that to close friends, I
rarely use ます forms (です remains however in some contexts). To people
introduced to me by friends, I will generally do the introduction in polite
forms and quickly transition to plain forms for most communication if that's
the pattern they are talking with my friends in. To people I meet through
other means, I will start with ます constructions and stick with them until I
feel comfortable around the person.

* * *

I might suggest the following equation where P(x) is the probability I use a
ます construction:

P(x) = A x [Their age - my age ] - B x [length of time I've known them] + C x
[business relationship > government office > acquaintance [~0] > friend of
friends [< 0] > direct friend relationship [<< 0] ] - E x [depth into the
conversation/message] + F x [written > 0 | spoken < 0]

Where A, B, C, D, E, and F are positive constants that vary somewhat by the
individual.

We could call it the "virial politeness law" (Cf.
<http://facstaff.cbu.edu/rprice/lectures/realgas.html>)

