Translation guide
In Japanese, auxiliary verbs attach to other verbs or adjectives to add grammatical meaning such as tense, aspect, mood, voice, politeness, or negation. They are essential for natural expression and often have no direct English equivalent.
Expressing when an action occurs or its state of completion
Past tense marker. Attaches to the 連用形 (masu-stem) of verbs. Indicates completed action or past state.
I watched a movie yesterday.
Progressive or resultative aspect. Indicates ongoing action or a state resulting from an action.
I am reading a book now.
The door is open.
Indicates a state resulting from an intentional action. Often used for preparations.
The window has been left open (on purpose).
Adjusting speech level for social context
Polite present/future tense auxiliary. Attaches to the 連用形. Used in formal situations.
I study Japanese every day.
Polite copula. Used with nouns and adjectives to make polite statements.
This is a book.
Expressing that something is not the case
Plain negative form. Attaches to the 未然形 (nai-stem) of verbs.
I don't eat meat.
Polite negative form. Used in formal contexts.
I don't eat meat. (polite)
Changing the voice or expressing ability
Passive or potential auxiliary. For godan verbs, 〜れる; for ichidan verbs, 〜られる. Context determines meaning.
I was praised by the teacher.
I can eat sushi.
Causative auxiliary. Indicates making or letting someone do something.
My mother made me eat vegetables.
Expressing wants or intentions
Expresses desire to do something. Attaches to the 連用形.
I want to go to Japan.
Volitional form. Expresses intention or invitation. Godan verbs use 〜う, ichidan verbs use 〜よう.
Let's watch a movie together.
Expressing uncertainty or hearsay
Auxiliary verbs in Japanese are bound morphemes that attach to verb stems. They cannot be used alone. When looking up 'auxiliary verb' in a dictionary, you will find grammatical explanations, not a single Japanese word.
It's more effective to learn these as part of verb conjugation patterns rather than as isolated words. Focus on the meaning each auxiliary adds to the base verb.