Plain style is the way you talk to friends, family and people younger than you. The meaning is the same as polite style (〜ます / 〜です), but it sounds close and relaxed. To teachers, customers, people you meet for the first time and people above you at work, use polite style. If you use plain style with them, it can sound rude. Plain style is also used in writing such as diaries.
§1Structure
End the sentence with a plain form instead of 〜ます / 〜です: 行きます → 行く, 高いです → 高い, 暇です → 暇だ, 休みです → 休みだ. Questions: drop か and say the end with a rising tone (行きますか → 行く？). In questions with a な-adjective or a noun, だ is dropped too (暇ですか → 暇？, 何ですか → 何？). The particles は, を, が and へ are often dropped (昼ごはん、食べた？). はい / いいえ become うん / ううん. よ and ね are added to the plain form (おいしいね, 暇だよ).
§2Examples
明日、暇？
あした、ひま？
Are you free tomorrow? (polite: 明日、暇ですか。)
うん、暇だよ。
うん、ひまだよ。
Yeah, I'm free. (polite: はい、暇ですよ。)
昨日、何食べた？
きのう、なにたべた？
What did you eat yesterday? (polite: 昨日、何を食べましたか。)
このケーキ、おいしいね。
このケーキ、おいしいね。
This cake is good, isn't it? (polite: このケーキはおいしいですね。)
ううん、今日は行かない。お金がないから。
ううん、きょうはいかない。おかねがないから。
No, I'm not going today. I don't have any money.
先週の旅行、とても楽しかった。
せんしゅうのりょこう、とてもたのしかった。
Last week's trip was a lot of fun.
明日は休みだから、いっしょに買い物に行かない？
あしたはやすみだから、いっしょにかいものにいかない？
Tomorrow is a day off, so do you want to go shopping together?
先生、明日の授業は何時からですか。
せんせい、あしたのじゅぎょうはなんじからですか。
Teacher, what time does tomorrow's class start? (to a teacher, keep polite style)
§3Common mistakes
- Keeping だ in a question. ✗ 明日、暇だ？ ✗ あの人、学生だ？ In casual questions with a な-adjective or a noun, drop both か and だ, and raise your voice at the end: ○ 明日、暇？ ○ あの人、学生？ In a statement, だ stays: 暇だよ.
- Adding だ after an い-adjective to make it casual. ✗ このケーキ、おいしいだ。 ✗ おいしいだよ。 Just take off です: ○ このケーキ、おいしい。 ○ おいしいよ。
- Using plain style with the wrong person, or mixing the two styles. Saying ✗ 先生、明日来る？ to a teacher sounds rude, so say ○ 先生、明日来ますか. With a friend, do not jump between 〜ます and plain endings in the same talk. Choose one style and keep it.
§4How it's different from similar grammar
- Polite style (〜ます / 〜です)
- The two styles say the same thing to different people. To a teacher: 昼ごはんはもう食べましたか。— はい、食べました。 To a friend: 昼ごはん、もう食べた？ — うん、食べた。 Polite style keeps the particles and か. Plain style often drops は, を and か, and it uses うん / ううん instead of はい / いいえ. When you are not sure which one to use, polite style is the safe choice.
- Plain form (the word forms)
- 普通形 (plain form) is the name of the word forms, such as 行く, 行かない, 行った and 暇だ. 普通体 (plain style) is a way of speaking in which you end your sentences with those forms. A plain form inside a polite sentence does not make it casual: 明日は暇だと思います is polite style. 明日は暇だと思う is plain style, because the end of the sentence is plain.
§5How this shows up on the JLPT
Plain style matters most in N5 listening. Talks between friends, classmates or family members are in plain style, with dropped particles and questions that have no か, such as どこ行く？ and もう食べた？. Practice hearing the rising tone as a question. In the grammar section, short dialogues between friends may ask you to choose an ending that matches the style, for example 行く？ — うん、行く. In reading, diary-like texts are written in plain style, so you must read 〜た and 〜だった as the past.
§6Quick check (3 questions)
1. You are talking to a close friend. Which is the natural casual way to ask 元気ですか?
げんきですか
2. You want to ask your teacher if he or she has had lunch. Which sentence is suitable?
3. Choose the answer that fits the blank. A: このかばん、高かった？ B: ううん、＿＿。
A: このかばん、たかかった？ B: ううん、＿＿。