Interrogative forms in Japanese are relatively simple. To create fundamental questions the question particle か (ka) is added after the closing verb. The word order in Japanese does not change, though the inflexion does.

明日、来ます。 → 明日、来ますか。
Ashita kimasu. → Ashita kimasu ka.
I'm coming tomorrow. → Are you coming tomorrow?

In the spoken language か is sometimes dropped. When the question particle か is dropped, the “u” from “-masu” becomes voiced, and a question mark is added. The same goes for “desu”.

明日、来ます。 → 明日、来ます?
Ashita kimasu. → Ashita kimasu?
I'm coming tomorrow. → Are you coming tomorrow?

In informal use か is hardly ever used. Men may use it on occasion to sound harsh.

明日、来る? → 明日、来るか。
Ashita kuru? → Ashita kuru ka.
Are you coming tomorrow? → Are you coming tomorrow, or what?

Note that when か is used the question mark is not. In informal use か (ka) is often replaced by の (no), followed by the question mark.

明日、来る? → 明日、来るの?
Ashita kuru? → Ashita kuru no?
Are you coming tomorrow? → Are you coming tomorrow?

You cannot use か (ka) and の (no) after the verb だ (da/to be), in this case, だ (da) is dropped, and か (ka) is placed directly after the noun. の (no) is preceded by な (na) when だ (da) is dropped.


猫だ。 → 猫か。
Neko da. → Neko ka.
It's a cat. → Is it a cat?

猫だ。 → 猫なの?
Neko da. → Neko na no?
It's a cat → Is it a cat?

Rhetoric questions

A rhetoric question is a question to which you don’t expect an answer, or to which you expect a confirming response. By replacing か (ka) with ね (ne) you can turn an interrogative question into a rhetoric question. The rhetoric particle ね (ne) can be used in both polite forms and informal forms.

明日、来ます。 → 明日、来ますか。 → 明日、来ますね。
Ashita kimasu. → Ashita kimasu ka. → Ashita kimasu ne.
I'm coming tomorrow. → Are you coming tomorrow? → You are coming tomorrow, right?

クモが怖かったね。
Kumo ga kowakatta ne.
The spider was scary, wasn't it?

そうね。
Sou ne.
It was, wasn't it?

Yes and No

The Japanese have several words for yes and no. For “yes”, はい (hai) and ええ (ee) are polite forms, うん (n) is used among friends. For “no”, いいえ (iie) and いえ (ie) are polite, and ううん (nn) is used between friends. The intonation of ううん starts high, drops and then rises again. うん and ううん aren’t words, but more sounds, like the English “uhuh”, and “uh-uh”.

Negative questions

Negative questions in the present/future tense can often serve as an invitation.

お茶を飲みませんか。
O-cha wo nomimasen ka.
Won't you have some tea?

お願いします。
Onegai shimasu.
Yes, please.

When replying to a negative question, the Japanese confirm or deny the statement made in the question with yes and no.

明日、行きませんか。
Ashita, ikimasen ka.
Aren't you going tomorrow?

紙がない?
Kami ga nai?
Isn't there any paper?

はい、行きません。
Hai, ikimasen.
Yes, I'm not going.

うん、ない。
Un, nai.
Yes, there isn't.

いいえ、行きます。
Iie, ikimasu.
No, I am going.


ううん、ある。
Nn, aru.
No, there is.

Be aware that はい and うん are also used to confirm that someone is listening. It does not necessarily mean that someone agrees to what you say.


明日、東京に行こう。
Ashita Toukyou ni ikou.
Let's go to Tokyo tomorrow.

うん。 N.

Non-commital sound

When answering you should always repeat the main verb, as shown above. Only はい or いいえ is not sufficient.

Requests

By stating a negative question, you can request someone to do something.

お茶を飲みませんか。
O-cha wo nomimasen ka.
Won’t you have some tea?

これをくださいませんか。
Kore wo kudasaimasen ka.
Won’t you please give me this?