Auxiliary verbs in Japanese


What are auxiliary verbs in Japanese language? Which verbs are auxiliary and
how to tell which are auxiliaries, and which are normal?

It looks like the word です is an auxiliary verb. But why? What tells us that it
has this function in sentence?

Is the word ます an auxiliary?

I apologize for silly questions.




There are two different definitions of _auxiliary verb_.

### _Auxiliary verb_ as the translation of **助動詞**

Words like ます, (ら)れる are generally taught as "part of conjugations/forms" in
most Japanese-as-a-second-language textbooks, but they are categorized as 助動詞
in monolingual Japanese dictionaries and grammar books. This word class is
usually translated as _auxiliary verb_ (or just _auxiliary_ ). The list of 助動詞
is relatively small (see below), and you may already be familiar with most of
them (as part of "forms"). Generally, 助動詞 is a mishmash of functional words
that work by modifying the meaning of the preceding word. Most auxiliary verbs
can conjugate, and multiple auxiliary verbs can be "stacked" to say
complicated things like "negative-causative-passive". For example, 飲ませられない
("is not forced to drink") is a verb 飲む followed by three auxiliary verbs
(causative させる, passive られる and negative ない). Despite its name, a 助動詞 does not
necessarily conjugate like a verb; for example, たい conjugates like an
i-adjective.

**List of Japanese 助動詞**

  * (さ)せる for causation
  * (ら)れる for passive voice, ability, etc
  * ない・ぬ・ん for negation
  * (よ)う for volition
  * まい for negative inference
  * たい・たがる for desire
  * た/だ for past tense
  * ようだ for similarity
  * そうだ for hearsay
  * らしい for hearsay, behavior
  * だ・です for predication/politeness (aka copula)
  * ます for politeness
  * やがる for disdain
  * べし for requirement/certainty
  * ...Plus some rare archaic auxiliary verbs and dialectal forms. See [this Wikipedia article](https://ja.wikipedia.org/wiki/%E5%8A%A9%E5%8B%95%E8%A9%9E_\(%E5%9B%BD%E6%96%87%E6%B3%95\)) (in Japanese) for the full list.

### _Auxiliary verb_ as the translation of **補助動詞**

Words like (～て)いる, (～て)みる, (～て)おく are usually called _subsidiary verbs_
(補助動詞), but some people like to call them _auxiliary verbs_. For details,
please see: [What is a subsidiary
verb?](https://japanese.stackexchange.com/q/18952/5010)

* * *

Regarding です/ます, yes, they are categorized as 助動詞 in Japanese monolingual
dictionaries. But I think most beginner Japanese-as-a-second-language
textbooks usually regard です as a (polite) copula and ます as a politeness
marker.

If you are a beginner, you may be overwhelmed by the number of "forms" in
Japanese verbs, but once you reach an intermediate level and start using
learning materials written in Japanese, you may want to familiarize yourself
with the concept of 助動詞. See also: [Why Japanese verb has so many
forms?](https://japanese.stackexchange.com/q/61902/5010)




There are two different definitions of _auxiliary verb_.

### _Auxiliary verb_ as the translation of **助動詞**

Words like ます, (ら)れる are generally taught as "part of conjugations/forms" in
most Japanese-as-a-second-language textbooks, but they are categorized as 助動詞
in monolingual Japanese dictionaries and grammar books. This word class is
usually translated as _auxiliary verb_ (or just _auxiliary_ ). The list of 助動詞
is relatively small (see below), and you may already be familiar with most of
them (as part of "forms"). Generally, 助動詞 is a mishmash of functional words
that work by modifying the meaning of the preceding word. Most auxiliary verbs
can conjugate, and multiple auxiliary verbs can be "stacked" to say
complicated things like "negative-causative-passive". For example, 飲ませられない
("is not forced to drink") is a verb 飲む followed by three auxiliary verbs
(causative させる, passive られる and negative ない). Despite its name, a 助動詞 does not
necessarily conjugate like a verb; for example, たい conjugates like an
i-adjective.

**List of Japanese 助動詞**

  * (さ)せる for causation
  * (ら)れる for passive voice, ability, etc
  * ない・ぬ・ん for negation
  * (よ)う for volition
  * まい for negative inference
  * たい・たがる for desire
  * た/だ for past tense
  * ようだ for similarity
  * そうだ for hearsay
  * らしい for hearsay, behavior
  * だ・です for predication/politeness (aka copula)
  * ます for politeness
  * やがる for disdain
  * べし for requirement/certainty
  * ...Plus some rare archaic auxiliary verbs and dialectal forms. See [this Wikipedia article](https://ja.wikipedia.org/wiki/%E5%8A%A9%E5%8B%95%E8%A9%9E_\(%E5%9B%BD%E6%96%87%E6%B3%95\)) (in Japanese) for the full list.

### _Auxiliary verb_ as the translation of **補助動詞**

Words like (～て)いる, (～て)みる, (～て)おく are usually called _subsidiary verbs_
(補助動詞), but some people like to call them _auxiliary verbs_. For details,
please see: [What is a subsidiary
verb?](https://japanese.stackexchange.com/q/18952/5010)

* * *

Regarding です/ます, yes, they are categorized as 助動詞 in Japanese monolingual
dictionaries. But I think most beginner Japanese-as-a-second-language
textbooks usually regard です as a (polite) copula and ます as a politeness
marker.

If you are a beginner, you may be overwhelmed by the number of "forms" in
Japanese verbs, but once you reach an intermediate level and start using
learning materials written in Japanese, you may want to familiarize yourself
with the concept of 助動詞. See also: [Why Japanese verb has so many
forms?](https://japanese.stackexchange.com/q/61902/5010)

