-(으)니
Since, Because
-니 is used to connect two clauses, where the first clause provides the reason or cause for the second. It often implies that the speaker discovered or realized the information in the second clause after performing the action in the first.
How It Works
-니 is a versatile connective ending that expresses a reason or cause. While it translates to 'because' or 'since', its core function is to link an action or state in the first clause to a subsequent discovery, realization, question, or command in the second clause.
Key Usages:
1. Discovery or Realization
The most distinct feature of -니 is that the speaker performs the action in the first clause and, as a result, discovers or realizes the situation in the second clause. It implies a sequence: Action → Discovery.
- 창문을 여니 시원한 바람이 들어왔다. (I opened the window and (found that) a cool breeze came in.)
- 집에 오니 아무도 없었다. (When I came home, I found that nobody was there.)
2. Reason for a Command or Proposal
Unlike -아/어서, -니 can be used to provide a reason for a command (-(으)세요) or a proposal (-자, -ㅂ시다). The reason is often something the speaker has just observed or realized.
- 날씨가 추우니 옷을 따뜻하게 입으세요. (Since the weather is cold, please dress warmly.)
- 시간이 없으니 서두르자. (Since we don't have time, let's hurry.)
3. Reason for a Question
It can also be used to ask a question based on the observation in the first clause.
- 그렇게 열심히 공부하니 피곤하지 않니? (You're studying so hard, so aren't you tired?)
Conjugation:
- Verb/Adjective stems ending in a vowel or ㄹ: Attach -니.
- 가다 → 가니 (since you go)
- 만들다 → 만드니 (since you make) - Verb/Adjective stems ending in a consonant (except ㄹ): Attach -으니.
- 먹다 → 먹으니 (since you eat)
- 좋다 → 좋으니 (since it's good)
Comparison with other 'because' forms:
- vs. -아/어서: -아/어서 shows a general, logical cause-and-effect and cannot be used with commands/proposals. -니 implies a personal discovery and can be used with commands/proposals.
- vs. -으니까: Both can be used with commands. -으니까 often gives a reason that is already known or is a subjective judgment to justify the following statement. -니 often presents a newly observed fact as the reason.
- vs. -더니: Both involve observation. -더니 is used when the speaker observes a change in someone or something else. -니 is used when the speaker's own action leads to a discovery.
Examples (5)
- 아침에 일어나니 눈이 와 있었다.
When I woke up in the morning, I found that it had snowed.
Word by Word: In the morning waking up, snow had come.
The act of waking up led to the discovery that it was snowing. This is a classic example of the 'discovery' nuance of -니.
- 밖에 나가니 비가 오고 있었어요.
When I went outside, I saw that it was raining.
Word by Word: Outside going out, rain was coming.
The speaker discovered it was raining only after the action of going outside.
- 피곤하니 오늘은 일찍 쉬세요.
Since you're tired, please rest early today.
Word by Word: Tired since, today early rest please.
-니 is used to provide a reason for a command (-(으)세요).
- 오랜만에 친구를 만나니 정말 반가웠다.
Meeting my friend for the first time in a while, I was really glad.
Word by Word: After a long time a friend meeting, really was glad.
The feeling of gladness is a direct result realized upon meeting the friend.
- 그 책을 다 읽으니 내용이 이해가 되네요.
Now that I've read the whole book, I understand the content.
Word by Word: That book all reading, content understanding becomes.
The understanding came as a result of finishing the book.
Common Mistakes
Using -아/어서 instead of -니 for commands or proposals.
Not Quite날씨가 좋아서 공원에 갑시다.Better날씨가 좋으니 공원에 갑시다.The grammar pattern -아/어서 cannot be followed by commands (like -(으)세요) or proposals (like -ㅂ시다 or -자). In these cases, you should use -니 or -으니까.
Using -니 for a general cause-and-effect relationship where no discovery is implied.
Not Quite버스가 늦게 도착하니 수업에 늦었어요.Better버스가 늦게 도착해서 수업에 늦었어요.-니 is best when the first clause leads to a new realization or discovery. For a simple, objective statement of cause and effect like this, -아/어서 or -기 때문에 is more natural.
Confusing -니 with -았/었더니 when the subject is the speaker.
Not Quite제가 열심히 공부하니 시험에 합격했어요.Better제가 열심히 공부했더니 시험에 합격했어요.When the speaker talks about the result of their own completed past action, -았/었더니 is used. It connects a past action to a subsequent result. In contrast, -니 is used when an action is the direct trigger for an immediate discovery or realization. The discovered situation can be in the past or present. For example, '집에 오니 아무도 없었다' (When I came home, I found nobody was there) is correct because coming home immediately led to the discovery.
Learn This First
To express formal reasoning 'since/because', you need causal pattern knowledge.
Related Patterns
- -아/어서Because of, Therefore
Both mean 'because', but -아/어서 is for general cause-and-effect and cannot be used with commands or proposals. -니 implies a personal discovery and can be used with commands.
- -더니I Noticed, And Then
Both involve observation or experience leading to a result. -더니 is used when the speaker observes a change in someone/something else, or when describing the result of their own past action. -니 is used when the speaker's present action leads to a discovery.
- -기 때문에Because
-기 때문에 is a more formal and objective way to state a reason ('due to the fact that...'). It lacks the personal nuance of discovery or immediate observation that is central to -니.