Polite vs Plain Form — Choosing the Right Register [JLPT N4]
Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026
“Tabemasu / taberu,” “ikimashita / itta” — switching between polite and plain by situation, with examples. (JLPT N4)
「行く」 to a friend, 「行きます」 to a boss — switch register by who you're talking to
To a friend you say 「今日、何する？」, but to a boss 「今日、何をしますか」 — Japanese has two speech styles: the polite style (です・ます) for courteous, distant settings (first meetings, work, seniors), and the plain style (だ・dictionary form) for close settings (friends, family, diaries). The wrong style is rude or overly distant. This guide teaches switching by “setting and listener,” and keeping “one style consistent within a passage.”
The two styles
- Polite (です・ます) = courteous, with distance: first meetings, work, seniors, customers. E.g. 私は学生です／毎日勉強します.
- Plain (だ・dictionary form) = close, casual: friends, family, diaries, social media. E.g. 私は学生だ／毎日勉強する.
Test: who's the listener? Unfamiliar／senior → polite; close／peer or junior → plain.
Styles compared
| Meaning | Polite | Plain |
|---|---|---|
| am a student | 学生です | 学生だ |
| study daily | 勉強します | 勉強する |
| won't go | 行きません | 行かない |
| tasty | おいしいです | おいしい |
Examples in use
- (first meeting) はじめまして、田中と申します。(Nice to meet you, I'm Tanaka.) — polite
- (among friends) 明日、映画見に行く？(Wanna go see a movie tomorrow?) — plain
- (to a boss) 今から向かいます。(I'm heading over now.) — polite
- (diary) 今日はいい天気だった。(The weather was nice today.) — plain
- (social media) 新しいカフェ、行ってきた！(Went to the new café!) — plain
⚠️ Easy traps to avoid
① Keep one style within a passage. Don't alternate 「です・ます」 one sentence and 「だ」 the next — for the same setting/listener, stay consistent (unless deliberately inserting an inner monologue).
② Default to polite for first meetings/work. When the relationship is unclear, polite is safest; switch to plain only after the other person does or you've clearly grown close. Jumping to plain (タメ口) with seniors is very rude.
③ Writing has its own 「である」 style. Papers/reports use 「である」 (〜である); diaries/novels use 「だ」. Polite style is common in letters and outward-facing documents.
🔄 Compare: polite／plain／である style
| Style | Setting | Example |
|---|---|---|
| polite (です・ます) | courteous, outward, seniors | 学生です |
| plain (だ style) | friends, diary, speech | 学生だ |
| である style | papers, formal writing | 学生である |
💡 An exam judgment tip
Speech style is Japanese's thermometer of “interpersonal distance” — getting it wrong isn't a grammar error, it's “rude or overly distant.” One safe rule: when unsure, start polite (です・ます), and switch to plain only after the other person clearly relaxes or you've grown close. Conversely, always using polite with a good friend feels standoffish. And a common slip: keep one style within a passage — don't hop between です・ます and だ. Mind these two and your Japanese reads as tactful.
❓ Common questions
Q: When do I use polite vs plain style?
By listener and setting: first meetings, work, seniors, customers → polite (です・ます); friends, family, diaries, social media → plain (だ・dictionary form). When unsure, polite is safest; switch once you've grown close or the other person goes plain first.
Q: Can I mix polite and plain?
Within one passage to one listener, not recommended — keep the style consistent, or it sounds jumpy. Exceptions exist: in polite speech, an inserted monologue like “（心想）疲れた…” can be plain; novels and casual speech also mix deliberately. As a beginner, first practice “one consistent style per passage.”
🖊️ Practice Quiz
Q1. When introducing yourself to someone for the first time, which register is appropriate?
(A) plain (田中だ。よろしく。)
(B) polite (田中と申します。よろしくお願いします。)
(C) either is fine
(D) depends
Q2. Conversation with a friend: 「今日何___？」(what did you do today?)
(A) しましたか (B) された？ (C) した？ (D) されましたか？
Q3. What is the colloquial plain contraction of 「食べています」?
(A) 食べてます (B) 食べてる (C) 食べる (D) 食べた
Q4. When writing a diary on social media, which register is generally used?
(A) polite (ます・です)
(B) plain (〜だ・〜た・dict. form)
(C) keigo (honorific/humble)
(D) classical/literary
Q5. Contacting your boss: 「今から___。」(reporting that you're going now)
(A) 行くよ (B) 行ってくる (C) 参ります (D) 行っちゃう
Answer Key
1. (B) ── a first-time self-introduction must use the polite register (ます・です), with humble forms (申します); plain would be rude.
2. (C) した？ ── friends use the plain register: 今日何した？
3. (B) 食べてる ── the plain colloquial contraction drops い: 食べている → 食べてる. (食べてます is the polite contraction.)
4. (B) ── social-media diaries generally use the plain register (〜だ/〜た/dict. form).
5. (C) 参ります ── to a boss, use the humble 参ります (humble of 行く).