せる・させる (Causative)
To make/let/have (somebody do something)
Structure
［る1］Verb ￫ 見
［る5］Verb ￫ 座
［う］Verb ￫ 歌
［く］Verb ￫ 歩
［す］Verb ￫ 話
［つ］Verb ￫ 打
［ぬ］Verb ￫ 死
［ぶ］Verb ￫ 飛
［む］Verb ￫ 休
［ぐ］Verb ￫ 泳
Exceptions:
する→させる
くる→ こさせる
Explanation
To convey that someone causes another person to perform an action, or allows them to, we attach the auxiliary verbs せる and させる to a verb. This grammatical function is known in Japanese as 使役 (causative), which means to make or let someone do something.
It's important to understand that せる and させる are not regular verb conjugations. Instead, they function as independent auxiliary verbs with their own specific meanings, much like other auxiliaries such as たい, ない, だ, and です.
To form the causative, for る-Verbs, you drop the final る and add させる. For う-Verbs, you change the final kana to the one in the 'あ' column of the same row (note that う becomes わ), and then attach せる (e.g., る becomes ら, む becomes ま, く becomes か).
- 母は子供に部屋を片付けさせる。The mother makes her child clean their room.
- 先生は学生に窓を閉めさせる。The teacher has the student close the window.
- 部長は部下にレポートを書かせた。The department manager had his subordinate write a report.
- 兄が僕のゲームをなくしたので、同じのを買わせます。My older brother lost my game, so I'm going to make him buy me the same one.
As is often the case, する and 来る are irregular. する changes entirely to させる, similar to how it becomes できる in the 'potential' form. 来る conjugates to 来させる.
- 難しい部分は田中さんにさせる。I'll have Tanaka do the difficult part.
- 彼女をがっかりさせるようなことは言いたくない。I don't want to say anything that would make her disappointed.
- こんな遠い所まで来させてごめんね。I'm sorry for making you come all this way.
- 彼を電話で起こして、すぐに来させる。I'll wake him up with a call and have him come right away.
Caution
In causative sentences, the person performing the action can be marked by either the particle に or を (but not が). This is because the grammatical subject (marked by が) is the one causing the action. Generally, using に suggests permission ('let'), whereas を carries a stronger sense of coercion ('make').
- 子供に公園に行かせる。To let a child go to the park.
- 子供を公園に行かせる。To make a child go to the park.
Fun Fact
Since the true agent in a causative sentence is the one marked by が (as is the case with all subjects), the literal interpretation of せる and させる can be understood through the core functions of the particles に and を.
(A) が (B) に話させる - (A) causes speaking 'in' (B).
(A) が (B) を話させる - (A) causes speaking 'through' (B).
This fundamental difference—に indicating a location or receiver of an action, and を marking a direct object—is what creates the subtle distinction between 'letting' and 'making' someone do something when used with the causative form.
Examples
その冗談は皆を笑わせた。
That joke made everyone laugh.
彼女を３０分も待たせた。
I made her wait for a whole 30 minutes.
医者は患者を歩かせて、足の様子を見た。
The doctor made the patient walk to check on their leg.
先生は学生に作文を書かせた。
The teacher made the students write an essay.
監督は遅刻した選手をグラウンド１０周走らせた。
The coach made the player who was late run 10 laps around the field.
子供たちを外で遊ばせてあげよう。
I'll let the kids play outside.
新人に会議の資料を準備させている。
I'm having the new employee prepare the materials for the meeting.
生徒たちがうるさかったので、みんなに教科書を読ませた。
The students were being noisy, so I made everyone read from the textbook.
彼は歌が下手だと言っていたのに、カラオケで歌わせた。
Even though he said he was a terrible singer, I made him sing at karaoke.
彼がゴロゴロしていたから、少し手伝わせた。
He was just lounging around, so I had him help out a bit.
病気の人には無理にでも水を飲ませなければならない。
You have to make a sick person drink water, even if it's by force.
息子がずっと頑張っていたから、欲しがっていたゲームを買わせてあげてよかった。
My son had been working so hard, so I'm glad I let him buy the game he wanted.