The causative is used to express “make” or “let” someone do something”. In fact, we’ve already met one way to form these expressions when 〜てもらう was introduced. As we saw, this structure was not entirely neutral—often implying that the speaker was grateful to the person performing the action.

The causative form introduced below lets us form a similar expression, but it is more neutral and closer in meaning to “make someone do”. Furthermore, depending on the context, it can also be used to mean “let someone do”. Let’s take a look at the verb conjugations.

### Group 1

We change the u-ending syllable to an a-ending syllable and add せる. The only exception is う-ending verbs where the ending syllable changes to わ.

### Group 2

For all group 2 verbs we remove the る and add させる.

Note, however, that some causative conjunctions are rarely used. させる, for example, means “to make see” but instead we would say “to show”, which is the verb せる.

### Group 3

The required particle for the person who will be made to perform the action depends on whether the verb is transitive or intransitive. For transitive verbs we require the target particle.

For intransitive verbs, the agent of the action takes the object particle.

And for those verbs that can be both transitive and intransitive (e.g. to wait), the correct particle will depend on the sentence structure.

Nor does the agent have to be a person. Certain verbs are effectively changed into transitive verbs by the causative. The intransitive verb “to finish” is probably the most common example.

The causative can be confusing for learners because there is no explicit distinction between “make someone do” and “let someone do”—the meaning is determined by the context.

This is clearly a request and so “let” is the appropriate translation.

The te form of the causative with あげる and くれる can be used to avoid ambiguity.

Care also needs to be taken when deciding between the causative and 〜てもらう. Below the first example sentence is more natural as it is in the translation. The second sentence is still grammatically correct, but would not be used.

Finally, in casual conversation the せて te form of the causative often gets transformed to して which is easier to pronounce.

We will see the combination of the te form of the causative and もらう later when honorifics are introduced.

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