Examples：出す/出る, 落とす/落ちる, 合う/合わせる, 見る/見える／見せる, etc
I can tell there are patterns for creating multiple verbs from the same root, but can’t find what this is called.
I know in Korean similar-looking endings change the valency (transitivity) of the verb, and come in verb “sets” with seven main endings: 우다, 구다, 추다, 이다, 기다, 치다 (ex: 보다 see vs. 보이다 be seen/show, 낮다 be low vs. 낮추다 to lower, 남다 remain vs. 남기다 to leave something behind/hand down).
So, are there set patterns for these Japanese verb “families,” and do the endings change valency or something else? What is this called in Japanese grammar?
6 comments
自動詞 (jidoushi) and 他動詞 (tadoushi), act-on-self and act-on-world.
They are referred as intransitive and transitive in English but I think it just makes things more confusing because you end up with intransitive verbs that still take a direct object: 空を飛ぶ
Same thing for the most part: transitive vs intransitive. I think most learning resources in English group them as “transitivity pairs”.
Unfortunately, I don’t think there’s any concrete rules that “this ending is always intransitive” or anything. You just have to learn them as you come across them.
Except for the 見る, 見える and 見せる you’ve listed. As you can see, they all have similar meanings, but I don’t know if there’s a specific name for such “groups”.
見る – to look/see/watch/etc
見える – can be seen (of something)
見せる – to show
For the most part (and definitely not in all cases), if the dictionary form ends in す, this indicates the verb is transitive. If it ends in る, it’s intransitive.
Unlike passive or causative verbs which are regularly derived from the basic verb form, there is a number of around 100 verb pairs of intransitive and transitive verbs that fall into a number of patterns, with some examples.
[Here is a list of 25 patterns (the last one isn`t a pattern)](https://pulin.hateblo.jp/entry/20150214/1423890973)
There are a few rules, but they all have exceptions.
But generally:
– if the couple is a/e the a will be intransitive and the e will be transitive. For example 止まる/止める
– if the couple is anything/す the す will be transitive and the other intransitive. Ex : 通る/通す
– ーう/ーえる couples are common but which one is transitive depends on the verb. Ex : in 開く/開ける the transitive one is 開ける but in 解く/解ける the transitive one is 解く。
In you examples, there is the exception of 合う/合わせる.
In this case it’s a causative form using the helper verb させる, which can be used to turn any verb into a new verb that means “making X do something”.
The opposite exists with the helper verb される which gives the meaning of “having X done to itself”.
If you are curious about origin of 見える and its relation to 見る you can read [the art about origin of 見える](https://www.reddit.com/r/LearnJapanese/comments/vfvruw/brief_japanese_%E8%81%9E%E3%81%93%E3%81%88%E3%82%8B%E8%A6%8B%E3%81%88%E3%82%8B%E8%A6%8B%E3%82%89%E3%82%8C%E3%82%8B_and_%E8%81%9E%E3%81%91%E3%82%8B_what_are/).