Japanese Verb Rules - Causative Form

Causative Form

This verb form expresses that one person causes another person do something.

How to derive the Causative form:

Group 1: Change the final る to させる
Group 2: Change the final vowel u to a and add せる
Group 3: くる→こさせる、する→させる

Consider the single vowel u （う） at the end of certain verbs such as kau （かう） as having the hidden consonant w before the vowel u. In other words, the original form of kau （かう） is ka(w)u. For example, the causative form of the verb かう is かわせる rather than かあせる.

How to use the form:

The causative form is used in a sentence to express that the Topic makes, forces, or lets the other do something.

The following sentence expresses that the Topic makes the Object do something:

せんせい		がくせい		に	ほん	ご		つか
先生	は	学生	に	日	本	語	を	使	わせます。

'The teacher makes his students use Japanese.'

In the following sentence, the Topic forces the other person do something (the use of the particle を rather than に after the noun indicating the other person, in this case, gives the sense of "forcing").

ちち		わたし		にほん		い
父	は	私	を	日本	に	行		かせました。

'My father forces me to go to Japan.'

In Japanese, when someone does someone else a favor, one of the giving verbs must follow the causative verb:

はは		わたし		にほん		りゅうがく
母	は	私	に	日本	に	留学	させてくれました。

'My mother allowed me to study in Japan.'

There is no causative form for honorific verbs: e.g. いらっしゃる ("be/go/come"), おっしゃる ("say")、くださる ("give me"). There is also no causative form for stative verbs:　e.g. ある ("need"), いる ( "exist"). Also, some verbs have morphologically related verbs that already have the causative meaning (e.g. 起（お）きる "wake up") has 起（お）こす "wake someone up").