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

  • welcomed or welcome ? Commented Jun 17, 2015 at 17:40
  • 8
    They take one drink, get drunk and all of a sudden, it's タメ語。
    – oldergod
    Commented Jun 24, 2015 at 0:41

5 Answers 5


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)


Shifting from polite speech to casual speech is usually a gradual and implicit process when a mature adult makes friends with someone. Depending on the situation, it may take months or even years to switch. Actually I often find myself using some polite sentences when I chat with people who have been my close friends more than 10 years.

Here are some random thoughts:

  • Upbeat, young, blue-collar or charai people are much quicker to adopt casual speech, whereas calm, older, white-collar, urban or otaku people tend to keep using polite speech longer. I basically belong to the latter category :)
  • IMO "go to an izakaya personally and you can drop keigo" is an oversimplification. Nevertheless, an izakaya is certainly a good place to try to start using a bit of casual speech.
  • Exclamatory phrases (especially i-adjectives) and jokes tend to be said in casual forms (すごい! 頑張れ!). です(か) in short sentences is often the first candidate of dropping (いつ? これ? 本当?)
  • Important and/or businesslike topics tend to be discussed in polite forms (e.g., making an appointment, paying at izakaya)
  • There are lots of useful intermediate, "softener" expressions and particles that allow you to avoid sounding overly friendly or remote. (e.g, 見ています → 見てます → 見てるよ → 見てる; 行きませんか → 行きません? → 行きます? → 行かない? → 行く?) Dropping particles like が/を, using contracted forms, choosing slangy/dialectal words and certain sentence-endings (っす, じゃん, etc) and so on are all relevant.
  • It's possible to explicitly invite someone to use casual speech (タメ口) if you think the other person is speaking too politely, but please note that being forced to use タメ口 can be sometimes stressful to a person like me. I never do this, and people around me almost never did it to me.
  • Many Japanese people believe that Western people prefer frank communications and that plain forms are easier to understand for foreigners. So what you experience as a foreigner may be a little different from what two native speakers normally do.
  • It's great to hear from a native speaker, thank you for your insight.
    – rjh
    Commented Jun 29, 2019 at 15:49

I think there's a lot of variation between speakers. Even as a foreigner at a university, I have met various types of speakers:

  • never use teineigo at all, even though I'm clearly older
  • people who use keigo for a few minutes and switch when I reply in casual form (most common)
  • people who use keigo for weeks, and say it's uncomfortable to use casual form because I am older; then switch once we are actually friends
  • people who use keigo forever even with close friends, simply because the friend is a staff member at the university

More traditional circles like taiko, martial arts etc. will use a lot of teineigo and mostly still conform to traditional sempai/kouhai structure.

However, other clubs such as my chorus group, while having a sempai/kouhai structure and showing a lot of respect for it, are looser. Some kouhai aren't even using teineigo here. Some sempai will use teineigo all the time, even when addressing kouhai - it's a bit of personal preference. In particular, for anything authoritative (e.g. meetings, orders, teaching), using polite form seems to be more appropriate than causal. In keeping with that, written form is much more likely to use teineigo.

I rarely hear 'baribari keigo', or keigo beyond teineigo. When talking to other members of your in-group about something a higher up (e.g. teacher) has done for you, use of passive form, くださる, いただく and お宅 etc. are common. The passive form of verbs is sometimes used for sempais. But it's rather thinly used in my experience. (I should quality that Japanese people still show an enormous amount of respect to higher ups, more so than Western countries, but language appears to play a smaller role in this than before)

  • Obvious note that this is not representative of relationships between two Japanese people (since I am a foreigner) but it does highlight the variation of attitudes among speakers.
    – rjh
    Commented Aug 20, 2022 at 23:17

In my personal experience, the transition from polite to plain form is done spontaneously, specifically if you are of the same age level or same position (at work).

A month or two after your introduction, you may switch to plain form if there are no inhibitions from your part of any kind, or you have done a milestone together (project closure, etc) . Otherwise, it is best to stick to polite form.

On the other hand though, it would be best if we err in the side of caution when we use plain form to people superior to our position (at work), or elderly people. In this case, I usually apply the polite form.


Whenever it feels right. This is probably not the answer you were looking for, so here are my observations:

  • If it's anything work related, or official, you stick to the polite language, no matter how well you know the person you are talking to.
  • As soon as you are doing something else in your private life, let's say having a beer together, it's okay to use the plain language. If the person is uncomfortable with that, he will most likely tell you.
  • People under 30 are more likely to switch to plain language when talking to someone of a similar age, even if they barely know each other.
  • Japanese are less likely to talk politely to you if you are a foreigner, because they want to make sure that you understand them.
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    Although I agree with the first three points, as someone living and working in Japan, I strongly disagree with your last point. They are only unlikely to speak to you in polite forms if initially you dont understand what they are saying or you request it. Commented Mar 11, 2016 at 0:14
  • @Chris Your post originally said 'more unlikely to talk politely'. Did you mean to write 'more likely to talk politely'?
    – user1478
    Commented Mar 17, 2016 at 1:43
  • @snailboat No, that's the experience I've made having been to Tokyo several times. I am 22 years old, so I was mostly talking to people around my age, and they don't seem to use keigo outside work that much. For example when a stranger asked me if it was okay to sit next to me he said "座っていいっす~?" Even when a middle aged man asked me for directions, he didn't use keigo. When I first went to Japan I got totally lost at Narita, and the staff at the information desk didn't speak keigo either. If I start the conversation in keigo I always get told not to be so polite.
    – Chris
    Commented Mar 17, 2016 at 8:54
  • Middle aged man is normal, if the person is older than you, they wouldn't necessarily use keigo. Narita staff is more surprising though. They've always been polite with me!
    – rjh
    Commented Jun 29, 2019 at 15:55

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