It is incredibly easy to turn a statement into a question in Japanese—all you need to do is add the particle か to the verb.
| 山田さん は 先生 です。 |
| Yamada-san is a teacher. |
| 山田さん は 先生 ですか？ |
| Is Yamada-san a teacher? |
| マイク は 水 を 飲みます。 |
| Mike will drink water. |
| マイク は 水 を 飲みますか？ |
| Will Mike drink water? |
In formal writing, there is no need for the question mark (it never used to exist in Japanese) as か makes it clear that the sentence is a question; however, in most non-literary texts it will be in included.
If we change the verb to the negative then we can use か to make a suggestion or an invitation.
| 一緒 に 食事 を しませんか？ |
| Won’t you have dinner together? |
| 飲み会 に 来ませんか？ |
| Won’t you come to the drinks? |
We can also add か to the standard form of the verb (this structure has a key grammatical function, as we shall see later); however, this is rarely a structure used to ask a question—it is too blunt. Instead, you will see の or なの added, depending on the sentence ending.
- の is used if the sentence ends in a verb or i-adjective
- なの is used if the sentence ends in a na-adjective or noun
| 今、忙しいの？ |
| Are you busy now? |
| その ビル は 学校なの？ |
| Is that building a hospital school? |
In casual conversation you can also put make the question in statement form and let a change in intonation do the rest, e.g. “You going?”
| 食べる？ |
| Will you eat? |
| ジョン は 会計士？ |
| Is John an accountant? |
Note that you will never hear this way of questioning used with the copula—either standard or polite.
ジョン は 会計士 だ？ (✘)
ジョン は 会計士 です？ (✘)