Introduction: What Kind of Words Are Particles and Auxiliary Verbs?
When reading or writing Japanese sentences, it is not just the words forming the sentence "framework" that matter. A huge role is played by "tiny words" that connect words together or add the speaker's feelings.
These are what we are learning today: particles (joshi) and auxiliary verbs (jodoushi)!
You might feel that "grammar has too many things to memorize and seems hard...", but don't worry! All we are doing is organizing the rules of Japanese that you already use naturally every day. Once you grasp the basic system, grammar questions on your Japanese exams will become a great way to rack up points, and your ability to read and write accurately will shoot up, too!
*Note: The overall rules for classifying parts of speech are covered in "Classification of Words," and how word forms change is covered in detail in the chapter on "Conjugation of Declinable Words (Yōgen)." Here, let's focus on the specific functions of particles and auxiliary verbs.
1. Similarities and Differences Between Particles and Auxiliary Verbs
Both particles and auxiliary verbs belong to a group called dependent words (fuzokugo).
Dependent words have two major characteristics:
(1) They cannot form a clause/phrase (bunsetsu) on their own. (They are always attached to the end of an independent word [jiritsugo].)
(2) They do not have an independent meaning by themselves. (They add meaning to independent words or show relationships between them.)
So, what is the difference between a particle and an auxiliary verb? There is only one key to telling them apart: "whether they conjugate (change their form) or not"!
・Particles (joshi): Do not conjugate (their form never changes).
Example: Sakura ga saku / Sakura ga saita (the form of "ga" never changes)
・Auxiliary verbs (jodoushi): Do conjugate (their form changes depending on what words follow them).
Example: Saka-nai / Saki-masu / Sai-ta ("nai", "masu", "ta", etc., change their forms)
[Key Takeaway]
When you spot a dependent word, check whether its form can change.
Does not change form (no conjugation) = Particle (joshi)
Changes form (conjugates) = Auxiliary verb (jodoushi)
2. Functions of Particles and Their 4 Groups
Particles are non-conjugating dependent words. Based on their function in a sentence, they are divided into the following 4 groups:
(1) Case-Marking Particles (Kaku-joshi)
Mainly attached to substantives / nouns (taigen), these particles indicate the role of that word in the sentence (such as subject, object, or modifier).
・Types: ga, no, o, ni, e, to, kara, yori, de, ya (A popular mnemonic in Japanese is: "Oni ga to yori deya")
Examples:
・Ame ga furu. (Indicates the subject: "Rain falls.")
・Hon o yomu. (Indicates the direct object / target of action: "Read a book.")
・Gakkō e iku. (Indicates direction: "Go to school.")
・Ie de benkyō suru. (Indicates location: "Study at home.")
・Kami to enpitsu o kau. (Indicates coordination / listing: "Buy paper and a pencil.")
(2) Conjunctive Particles (Setsuzoku-joshi)
Mainly attached to declinable words / predicates (yōgen: verbs, adjectives, adjectival nouns), these particles connect a preceding clause or sentence to the one that follows.
・Types: ba, to, temo (demo), keredo (keredomo), ga, noni, node, kara, shi, te (de), nagara, tari (dari), etc.
Examples:
・Haru ga kureba atatakaku naru. (Condition: "If spring comes, it gets warm.")
・Ame ga futta node kasa o sashita. (Cause / reason: "Because it rained, I opened an umbrella.")
・Hashitta keredo maniawanakatta. (Contrast / adversative: "I ran, but I didn't make it in time.")
・Utainagara aruku. (Simultaneous action: "Walk while singing.")
(3) Adverbial Particles (Fuku-joshi)
Attached to various types of words, these particles add special nuances such as limitation, emphasis, or degree to the words that follow. Like adverbs, they allow the attached phrase to modify the subsequent predicates.
・Types: wa, mo, koso, sae, demo, shika, bakari, dake, hodo, kurai (gurai), nado, etc.
Examples:
・Watashi wa iku. (Topic marker / distinguishing from others: "As for me, I will go.")
・Kimi mo kuru? (Addition / inclusion: "Are you coming too?")
・Hyaku-en dake aru. (Limitation: "I only have 100 yen.")
・Ima koso gambarō. (Emphasis: "Now is the very time to do our best.")
(4) Sentence-Ending Particles (Shū-joshi)
Mainly attached to the very end of a sentence, these particles express the speaker's feelings, such as doubt/questioning, emotional exclamation, prohibition, or calling out to someone.
・Types: ka, na, ne, yo, wa, zo, tomo, kashira, etc.
Examples:
・Ashita wa hareru ka. (Question: "Will it be sunny tomorrow?")
・Heya ni haitte wa ikena. (Prohibition: "Do not enter the room.")
・Kirei na keshiki da ne. (Exclamation / seeking agreement: "It's a beautiful view, isn't it?")
・Boku ga tetsudau yo. (Informing / asserting: "I'll help you, you know!")
[Trivia] The Difference Between "Wa" and "Ga"
What is the difference between "Watashi ga hashiru" and "Watashi wa hashiru"?
The case-marking particle "ga" directly specifies the subject. The spotlight shines right on the subject itself, answering: "Who is running? → I am running."
On the other hand, the adverbial particle "wa" brings up a topic. The spotlight shifts to the predicate action that follows: "As for me (I don't know about others, but), I am running." Just changing one single particle completely alters the nuance of a sentence—that is one of the fascinating things about Japanese!
3. Functions and Main Meanings of Auxiliary Verbs
Auxiliary verbs are dependent words that conjugate. They attach to the ends of verbs, nouns, and other words to add a variety of meanings to the sentence.
Let's organize and learn the primary auxiliary verbs taught in junior high school by their meanings!
(1) Passive, Potential, Spontaneous, Honorific: reru / rareru
・Passive (to be ~ed): Sensei ni homerareru. (To be praised by the teacher.)
・Potential (can do ~): Sakana ga taberareru. (Can eat fish.)
・Spontaneous (naturally comes to mind / happens on its own): Mukashi no koto ga omoikasareru. (Memories of the past come naturally to mind.)
・Honorific (showing respect to the subject): Kōchō-sensei ga hanasareru. (The principal speaks.)
(2) Causative: seru / saseru
Adds the meaning of making or letting someone do an action.
Examples: Otōto ni heya o sōji saseru. (Make my younger brother clean the room.) / Imōto o kaimono ni ikaseru. (Send my younger sister shopping.)
(3) Negative: nai / nu (n)
Negates an action or state ("does not / is not").
Examples: Asa-gohan o tabenai. (Do not eat breakfast.) / Yowane o hakanu. (Do not utter complaints.)
(4) Desiderative (Desire / Wish): tai / tagaru
Expresses a desire or wish to do something ("want to ~").
Examples: Hon o yomitai. (I want to read a book.) / Otōto ga soto e detagaru. (My younger brother wants to go outside.)
(5) Past, Perfective, Continuative: ta (da)
・Past (events in the past): Kinō, hon o yonda. (I read a book yesterday.)
・Perfective / Completed (completely finished): Shukudai ga ima owatta. (The homework has just finished.)
・Continuative / Resulting State (an ongoing state resulting from an action): Magatta michi. (A curved / winding road.)
(6) Volitional, Conjectural, Invitative: u / yō
・Conjectural (probably / perhaps): Ashita wa hareru darou. (It will probably be sunny tomorrow.)
・Volitional (intention: "I shall / will"): Boku ga yarou. (I will do it.)
・Invitative (invitation: "Let's ~"): Issho ni kaerou. (Let's go home together.)
(7) Polite: masu
Used to make speech polite towards the listener.
Example: Kore kara hajimemasu. (We will begin now.)
(8) Assertive / Copula: da / desu
Adds a clear assertion ("it is / to be"). "Desu" is the polite form of assertion.
Examples: Ashita wa nichiyōbi da. (Tomorrow is Sunday.) / Watashi wa seito desu. (I am a student.)
(9) Conjectural, Simile / Exemplification: yōda (yōdesu) / midaida (mitaidesu)
・Conjectural / Inference (seems like ~): Soto wa samui yōda. (It seems cold outside.)
・Simile / Comparison (just like ~): Kōri no yōni tsumetai te. (Hands as cold as ice.)
・Exemplification (such as ~): Fuji-san no yōna takai yama. (A high mountain like Mt. Fuji.)
(10) Hearsay, Conjectural Appearance: sōda (sōdesu)
・Hearsay (I heard that ~): Ashita wa ame ga furu sōda. (I hear it will rain tomorrow.)
・Appearance / Conjectural state (looks like it is about to ~): Ame ga furi sōda. (It looks like it's going to rain.)
(11) Conjectural / Evidential: rashii
Expresses an inference based on reliable grounds or evidence ("it seems / apparently").
Example: Dōyara hontō no rashii. (Apparently, it seems to be true.)
[Key Takeaway] About Auxiliary Verb Conjugations
Just like declinable words (verbs/adjectives), auxiliary verbs change their forms depending on what comes after them.
For example, the negative auxiliary verb "nai" conjugates just like an adjective (nakaro, nakat, nai, nai, nakere, 〇). The polite auxiliary verb "masu" undergoes a unique conjugation (masho, mashi, masu, masu, masure, mase/mashi).
Rather than trying to memorize every single conjugation table by heart, it is much easier to recall forms by mentally attaching following words to see how they sound naturally!
4. Boost Your Test Scores! Identification Tips and Common Mistakes
The most frequently tested topic on high school entrance exams and school midterms/finals is "distinguishing between words that share the same sound or similar appearance." Let's master these identification tricks!
Identification 1: Telling "Nai" Apart (Auxiliary Verb vs. Adjective)
When "nai" appears in a sentence, questions often ask whether it is an auxiliary verb or an adjective (an independent word).
・Auxiliary verb "nai": Preceded by a verb, expressing negation. Can be replaced with "nu"!
Example: Hon o yomanai. → Hon o yomanu. (Can be replaced, so it is an auxiliary verb.)
・Adjective "nai": An independent word that means "does not exist" or "not present" on its own. Cannot be replaced with "nu"!
Example: Okane ga nai. → Okane ga nu (Unnatural! Therefore, it is an adjective.)
*Hint: If you can insert a particle like "wa" or "ga" right before it, it is an adjective. (Example: Omoshiroku nai → Omoshiroku wa nai)
Identification 2: Telling "Rashii" Apart (Auxiliary Verb vs. Suffix + Adjective)
・Auxiliary verb "rashii": Inference/supposition ("it seems like..."). Attaches to the terminal form of verbs, etc.
Example: Ame ga furu rashii. (furu + rashii = auxiliary verb)
・Suffix (forming an adjective) "rashii": Attaches to a noun to mean "having qualities appropriate for... / -like / manly / student-like".
Example: Otokorashii taido (manly attitude) / Chūgakuseirashii kōdō (behavior fitting for a junior high student). (Attaches to a noun to form a single adjective, so it is not an auxiliary verb.)
Identification 3: Telling "Da" Apart (Auxiliary Verb vs. Inflectional Ending of an Adjectival Noun)
When you see "da" at the end of a clause or sentence, ask yourself whether it is an assertive auxiliary verb or the inflectional ending of an adjectival noun (keiyō-dōshi).
・Auxiliary verb "da": Attaches after a noun (substantive).
Example: Kore wa hon da. ("Hon" is a noun, so "da" is an assertive auxiliary verb.)
・Inflectional ending of an adjectival noun: Part of a word describing a state or condition where you could add "totemo" (very).
Example: Niwa ga shizuka da. ("Shizukada" as a whole is a single adjectival noun. Since you can say "totemo shizukada" [very quiet], the ending "da" cannot be separated on its own as an auxiliary verb.)
[Common Mistake] Particle "Ni" vs. Auxiliary Verb "Ni"
The single kana character "ni" can have multiple identities!
・Tōkyō ni iku. → Attaches to a noun to show direction; it is a case-marking particle.
・Kare wa isha ni natta. → The continuative form (ren'yōkei) of the assertive auxiliary verb "da" (meaning "became a doctor").
・Heya o kireini sōji suru. → The continuative ending of the adjectival noun "kireida".
Avoid making a snap judgment from just one character. Always build the habit of analyzing the entire sentence structure by asking: "What is its base (dictionary) form?" and "Is it part of an independent word, or is it a dependent word?"
Summary: Key Points to Remember!
・Dependent words (fuzokugo) attach to independent words to add meaning (they cannot form a bunsetsu alone).
・Particles (joshi) are dependent words that do not conjugate. There are 4 types: Case-marking, Conjunctive, Adverbial, and Sentence-ending.
・Auxiliary verbs (jodoushi) are dependent words that do conjugate. They enrich sentences with meanings like passive, negative, past, desire, assertion, and more.
・For tricky words, distinguish them by testing whether "they can be replaced with another word (like nu)" or "whether they are simply part of an independent word"!
Once you understand particles and auxiliary verbs properly, sentence structures will become crystal clear. When you read your everyday textbooks, try being mindful of them: "Ah, here's a conjunctive particle!" or "This auxiliary verb indicates inference!"