のだ
Explanation
だ・です ending sentence: Add の before だ・です
Nouns/な Adjectives: なのだ
Verbs/い Adjectives: + のだ
のだ or のです generally speaking, marks known or new information.
It’s kind of like “you know?” in English.
The basic usages and meanings of のだ are:
- Giving additional information or explanations.
- Pressing for more information with questions.
Stronger and generally wants more detail than a normal question. - Emphasis on information that should be known, or on intent.
の frequently gets abbreviated to ん。
Additional information
That’s why
This is how
It’s true
The most basic use of のだ is to provide additional information.
It generally shouldn’t be used to give information out of the blue.
This means you should use it when someone else is probably asking themselves a question.
Explanations
You may think of this use as a simple explanatory statement.
It is most appropriate as a response to a question, to explain something, or to clear up confusion.
- こう使うんだ – This is how you use it. (Other person couldn’t seem to figure it out).
- 猫は水がきらいなのだ – Cats hate water. (Probably after seeing a cat react badly to water)
- いま、おなかが空いているんだ – I’m hungry now (that’s why I don’t have energy)
With から however, it takes on a harsh tone (You should know that):
- 先生の話を聞かなかったから、わからないんだ。- You didn’t listen to the teacher, that’s why you don’t understand.
Educated Guesses
のだ may also be used to make educated guesses:
- 暑いんですか？- Are you hot? (I think you look hot)
- 彼は休憩中なんですか – Is he on break now? (Looked around, didn’t see him)
- だから掃除したんだね – So that’s why you cleaned, right?
Questions
Tell me more
With questions, のだ asks for an explanation, sort of like “tell me more”.
In conversations, this also shows a level of engagement.
Examples
- どうするのだ？- What are you going to do? (tell me)
- 食べたんですか？ – So, did you eat it? (I want to know).
- で、だれが来たんですか？ – So, who came?
Emphasis
You should know
Definitely will
This last usage is tricky. It exists because of the meaning of new information. However, if this information is already known, it can imply a few things:
Obvious Information
のだ can imply that the information should be known. This is commonly used with よ。
This will most likely be rude.
- 今、別の人を手伝っているんだよ。- I’m helping someone else right now (Can’t you see?)
- 今、寝ているんだけど – I’m sleeping right now but.. (You can see that..is it urgent?)
- うるさいんだけど – You’re pretty loud (You realize that) –> Actual meaning: Shut up.
Resolve
のだ can additionally express resolve. It strengthens the intent of the statement.
This can be used towards other people.
- もう帰るんだ – I’m going home now (I’ve had enough)
- これから寝るんだ – I’m going to go to bed now.
- そうじするのだ – I’m going to clean/You’re going to clean.
- 何としてもやるんだ – Do whatever it takes.
- 今夜はしっかり勉強するんだね – (We know) You’re going to study properly tonight, right?
The Most Common Mistake
のだ must be used for to give or request additional information or as an educated guess. This means there must be a basis to use のだ. (With the intent meaning, the basis is the background information)
This means that you cannot use のだ when you or they have no information available.
- 私は田中さんなんです– I’m Tanaka san (You have information about me already) ✖
Not realistic that your name isn’t the first thing people learn about you. - だれかいるんですか？ – Is someone here? (Absent hearing a sound, you can’t say this).
References
This was a pretty hard one to write. This explanation has been helped greatly by these sources:
Stack Exchange (If you read one of these, read this one)
Stack Exchange 2 (Ok, has examples)
Weblio (Japanese definition)
Kotobank (Slightly different Japanese definitions)
Kotobaken (Long winded Japanese explanation of prior information)