Video
Let’s watch this short video for a quick overview.
Source: gokigen japanese official YouTube Channel
Introduction
In English, we often say things like:
- “It became cold.”
- “I became a teacher.”
- “It got quiet.”
But how do you say “become” or “get” in Japanese?
In this article, we’ll learn how to express changes or transitions in Japanese using two important grammar structures:
- 〜くなる for い-adjectives
- 〜になる for な-adjectives and nouns
Let’s master how to describe what something or someone has become — naturally and correctly!
1. The Basic Pattern
For い-adjectives (i-adjectives):
Remove the final い, then add くなる.
| Adjective | Becomes… |
|---|---|
| あたたかい | あたたかくなる (become warm) |
| たのしい | たのしくなる (become fun) |
| ねむい | ねむくなる (get sleepy) |
For な-adjectives (na-adjectives):
Remove the final な, then add になる. (Use the adjective stem + になる)
| Adjective | Becomes… |
|---|---|
| しずか（な） | しずかになる (become quiet) |
| しあわせ（な） | しあわせになる (become happy) |
| たいへん（な） | たいへんになる (become difficult/hard) |
For nouns:
Just add になる after the noun.
| Noun | Becomes… |
|---|---|
| 医者 | 医者になる (become a doctor) |
| 看護師 | 看護師になる (become a nurse) |
| 冬 | 冬になる (it becomes winter) |
2. Examples in Action
Using 〜くなる
- 日本語の勉強が楽しくなりました。
= Studying Japanese has become fun. - 冬になると、寒くなります。
= When it becomes winter, it gets cold. - 昨日の夜、寝ませんでした。今日、会社で眠くなりました。
= I did not sleep last night. Today, I fell asleep at work.
Using 〜になる
- 練習して、ピアノが上手になりました。
= I have been practicing and getting better at the piano. - メイさんは会社員になりました。
= Mei became an office worker. - 掃除して、部屋がきれいになりました。
= After cleaning, the room became clean.
3. Common Mistakes to Avoid
| Incorrect ❌ | Correct ✅ |
|---|---|
| 便利くなる | 便利になる (便利 is a な-adjective) |
| 楽しいになる | 楽しくなる (楽しい is an い-adjective) |
💡 Tip: Always double-check the adjective type before conjugating!
4. Practice Time!
Change these to “become” sentences:
| Word | Type | Becomes… |
|---|---|---|
| おそい (slow/late) | い-adjective | おそくなる |
| すずしい (cool) | い-adjective | すずしくなる |
| しあわせ（な） | な-adjective | しあわせになる |
| たいへん（な） | な-adjective | たいへんになる |
| 医者 | noun | 医者になる |
| 雪 | noun | 雪になる |
5. FAQ – Frequently Asked Questions
- QCan I use 〜くなる and 〜になる in the past or future tense?
- A
Yes! They follow regular conjugation rules:
- くなる → くなった (past), くなります (polite)
- になる → になった (past), になります (polite)
- QWhat if I’m not sure if it’s a な-adjective or い-adjective?
- A
Check the ending:
- い-adjectives usually end in い (e.g. あたたかい → あたたかくなる)
- な-adjectives do not, and need な before a noun (e.g. きれいな → きれいになる)
- QWhat’s the difference between 〜になる (ni naru) and 〜にする (ni suru)?
- A
- 〜になる (ni naru): Means something becomes, gets, or turns into something naturally or as a result of a process. (Ex: 冬になる – Fuyu ni naru – It becomes winter; 彼は医者になった – Kare wa isha ni natta – He became a doctor).
- 〜にする (ni suru): Means someone decides on something (Ex: コーヒーにする – Koohii ni suru – I’ll have coffee) or actively makes something a certain way (Ex: 部屋をきれいにする – Heya o kirei ni suru – I make the room clean).
- Think: なる = happens, する = someone does/decides.
- QCan I use these forms to talk about becoming able to do something (like “become able to swim”)?
- A
You don’t use 〜くなる or 〜になる directly with verbs for this. To say you “become able to do” something, you use the potential form of the verb followed by 〜ように な る (you ni naru).
Example: 泳げるようになりました (Oyogeru you ni narimashita – I became able to swim). This is a separate but very important pattern!
- QCan 〜くなる / 〜になる express a gradual change over time?
- A
Yes, these forms often describe the result of a change that happened over time. To specifically emphasize that a change is in progress or happening gradually, you can use the 〜てくる (te kuru) form: 〜くなってくる (ku natte kuru) or 〜になってくる (ni natte kuru).
Example: だんだん日本語が上手になってきました (Dandan Nihongo ga jouzu ni natte kimashita – My Japanese has gradually been getting better).
6. Conclusion
Now you can confidently describe change and transformation in Japanese using:
✅ 〜くなる for い-adjectives
✅ 〜になる for な-adjectives and nouns
✅ Real-life examples to express how things or people become something else
🎯 Try this: Write 3 things about how your life has changed since starting to learn Japanese. Use 〜くなった and 〜になった!
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