Introduction
If you’ve been learning Japanese, you probably know how to say things politely using です (desu) and じゃないです (janaidesu). But in real-life conversations—especially with friends, family, or peers—native speakers often drop the polite endings and use short forms, also called plain forms.
In this article, you’ll learn how to use short forms for adjectives and nouns naturally in casual Japanese. This skill will help you understand everyday speech, express your feelings more freely, and build the foundation for more complex grammar later on.
1. What Is the Plain Form (Short Form)?
The plain form is the informal version of adjectives and nouns. It’s commonly used in:
- Casual conversations
- Manga, anime, and texting
- Grammar patterns (e.g., 〜と思います, 〜かもしれない)
Here’s how they differ from the polite form:
| Type | Polite Form | Plain (Short) Form |
|---|---|---|
| い-adjective | おいしいです | おいしい |
| い-adjective (negative) | おいしくないです | おいしくない |
| な-adjective | げんきです | げんきだ |
| な-adjective (negative) | げんきじゃないです | げんきじゃない |
| Noun | 学生です | 学生だ |
| Noun (negative) | 学生じゃないです | 学生じゃない |
2. How to Conjugate Adjective and Noun Short Forms
い-Adjectives
- Affirmative: Remove です from long forms (Keep the base form)
- たのしい
です→ たのしい
- たのしい
- Negative: Remove です from the polite negative
- たのしくない
です→ たのしくない
- たのしくない
な-Adjectives & Nouns
- Affirmative: Replace です with だ
- ひまです → ひまだ
- 先生です → 先生だ
- Negative: Remove です
- ひまじゃない
です→ ひまじゃない - 先生じゃない
です→ 先生じゃない
- ひまじゃない
📝 Note: In casual speech, even だ is often omitted!
ひまだ → ひま
先生だ → 先生
3. How Are Plain Forms Used in Conversation?
Short forms help your speech sound natural and relaxed. They are less formal but very common in casual settings.
Example Sentences:
| Polite | Plain |
|---|---|
| このりんごはおいしいです。 This apple is delicious. | このりんご、おいしい！ This apple, delicious! (Note: Retaining the exclamation mark reflects the casual, sometimes exclamatory nature of plain forms.) |
| 日曜日はひまですか？ Are you free on Sunday? | 日曜日、ひま？ Free on Sunday? |
| いいえ、ひまじゃないです。 No, I am not free. | ううん、ひまじゃない。 Nope, not free. / Nah, I’m not free. (Note: “ううん” is a casual “no,” often translated as “nope,” “nah,” or “uh-uh.”) |
| ジムさんは大学生ですか？ Jim, are you a college student? | ジムさんは大学生？ Jim, are you a college student? |
| いいえ、大学生じゃないです。 No, I am not a college student. | ううん、大学生じゃない。 Nope, not a college student. |
4. Tips for Natural-Sounding Informal Speech
No “か” for Questions
When asking questions, use short forms and raise the pitch at the end of the sentence.
We do not use the question particle か with short forms.
- お母さんは元気？(⤴) – How is your mother?
- この本、おもしろい？(⤴) – Is this book interesting?
Add Particles Like よ, ね, な
In casual speech, we often add particles like ね, よ, or な to the end of a sentence to convey subtle feelings attached to what we say.
- 暑いね。= It’s hot, isn’t it?
- 暑いよ。= It’s hot, you know.
- 暑いな。= It’s hot, huh. (to self)
Note that when adding those particles to な-adjectives and nouns, they do require だ before the particle.
- A: 野菜は好き？ – Do you like vegatables?
B: うん、好きだよ。- Yeah, I do. - A: 妹 は 高校 何年生？ – What year is your sister in high school?
B: 二年生だよ。- She is a second year student.
5. Let’s Practice!
Change the following polite forms into short forms:
| Polite | Plain |
|---|---|
| 新しいです | 新しい |
| 静かです | 静かだ |
| 暑くないです | 暑くない |
| 親切です | 親切だ |
| 弁護士じゃないです | 弁護士じゃない |
Practice Dialogue:
ピザは好き？
Do you like pizza?
うん、好き（だよ）。
Yes, I like it.
今日はひま？
Free today?
ううん、ひまじゃない（よ）。
Nope, not free.
6. FAQ – Frequently Asked Questions
- QCan I always use “だ” at the end of な-adjectives and nouns?
- A
You can, but in casual spoken Japanese, it’s often omitted. Saying “ひま” or “学生” alone sounds more natural in casual speech. Use “だ” when needed for grammar patterns or to add emphasis.
- QWhy do we say “noun じゃない” instead of “noun ではない” in plain form?
- A
“じゃない” is the colloquial form of “ではない.” It’s shorter and more common in conversation. Both are grammatically correct, but “じゃない” is more natural for speaking.
- QCan I use short forms in writing?
- A
Only in informal contexts, like texting or journaling. For formal writing or business emails, stick to polite forms.
- QAre the rules for using plain form adjectives/nouns the same as for verbs (e.g., only with friends/family)?
- A
Yes, exactly! The social rules are the same. Use plain forms (for verbs, adjectives, and nouns) in casual situations with people you know well (friends, family, close peers) or those younger than you. Avoid them in formal settings or when speaking to strangers, superiors, teachers, etc., to show politeness. Stick with です/ます forms when in doubt.
- QHow do I make the past tense plain form for adjectives and nouns?
- A
For the past tense:
な-Adjectives & Nouns: Add だった (datta) to the stem/noun.
Ex: きれい(だ) → きれいだった – was pretty; 学生(だ) → 学生だった – was a student Negative: きれいじゃない → きれいじゃなかった (kirei janakatta).い-Adjectives: Change the final い (i) to かった (katta).
Ex: おいしい → おいしかった – oishikatta – was delicious
Negative: おいしくない → おいしくなかった (oishikunakatta).
- QCan I use sentence particles like よ (yo), ね (ne), な (na) with negative plain forms too? (e.g., ひまじゃないよ – hima janai yo?)
- A
Absolutely! Sentence particles like よ (yo), ね (ne), な (na), etc., work perfectly with negative plain forms to add emotion or nuance, just like with affirmative ones. For example: 「これは好きじゃないよ。」(Kore wa suki janai yo. – I don’t like this, you know.), 「今日は暑くないね。」(Kyou wa atsukunai ne. – It’s not hot today, huh?).
Conclusion
Learning the plain form of adjectives and nouns is an essential skill for anyone who wants to speak Japanese naturally. These short forms are the building blocks for friendly conversations, manga dialogue, and more complex sentence structures you’ll learn in future lessons.
✅ Practice forming short forms
✅ Use them in daily chats
✅ Get used to how they sound in real life
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