A Step-by-Step Guide to Classifying Words (Parts of Speech)
When you hear the word "grammar," you might think, "There's so much to memorize, it sounds really hard..." Don't worry if it seems tricky at first—you've got this!
Classifying parts of speech is just like solving a sorting puzzle: all you need to do is answer a few simple questions, and you'll find the right category every time.
Once you understand the rules for grouping words, your reading comprehension and writing skills will get a massive boost of confidence. Let's take it one step at a time, starting with the basics!
Step 1: Essential Knowledge Before Identifying Words
Before sorting words into parts of speech, let's review the basic units of language, starting with the word (tango).
We can break down language from largest to smallest as follows:
Sentence (bun): A complete unit of thought, from the first character to the full stop ("。").
↓
Phrase (bunsetsu): The smallest natural-sounding unit of speech (you can test this by inserting little pause words like "ne" or "sa" between them).
Example: Sakura ga (ne) / kirei ni (ne) / saku (ne).
↓
Word (tango): The smallest meaningful unit of language, obtained by breaking down phrases even further until they cannot be split without losing their meaning.
Example: Sakura / ga / kirei ni / saku
[Key Point]
Parts of speech are simply these "words" sorted into 10 groups based on their characteristics and grammatical functions. Never try to classify a whole phrase (bunsetsu)—the golden rule is to always break it down into individual words first!
Step 2: The Two Major Criteria for Classification
Every single Japanese word (part of speech) can be organized using just two basic questions.
Criterion 1: Independent Word (Jiritsugo) or Dependent Word (Fuzokugo)?
You can tell them apart by asking whether the word can make sense entirely on its own.
- Independent Words (jiritsugo): Words that have an independent, clear meaning on their own and can stand at the beginning of a phrase (bunsetsu).
Examples: hon (book), hashiru (run), utsukushii (beautiful), totemo (very), shikashi (however)
- Dependent Words (fuzokugo): Words that do not form a complete meaning on their own and must always attach to the end of an independent word. They can never start a phrase (bunsetsu).
Examples: ga, o, ni, nai, masu, da
Criterion 2: Inflected (Katsuyō) or Uninflected?
You can tell them apart by checking whether the ending of the word changes (conjugates/inflects) depending on what follows it.
- Words with Inflection: Words whose form changes.
Example: "kaku" (to write) → kakanai, kakimasu, kakeba (the word ending changes)
- Words without Inflection: Words whose form stays exactly the same, no matter what sentence they appear in.
Examples: "tsukue" (desk), "totemo" (very), "ano" (that), "shikashi" (however) (forms never change)
(*Detailed types and forms of inflection are covered in the chapter "Inflection of Words.")
Step 3: The Complete Map of the Ten Parts of Speech (Jippinshi)
All Japanese words are classified into 10 parts of speech. Keep this mental roadmap in mind, and you will never get lost!
[Independent Words (Jiritsugo)] (8 in total)
◆ Inflected (Declinable Words / Predicates: Yōgen)
1. Verbs (Dōshi) (express actions, occurrences, or existence)
2. Adjectives (Keiyōshi) (express nature, qualities, or states)
3. Adjectival Nouns (Keiyōdōshi) (express nature, qualities, or states)
◆ Uninflected
4. Nouns (Substantives: Taigen) (can act as the grammatical subject; names of people, things, concepts)
5. Adverbs (Fukushi) (primarily modify yōgen)
6. Prenouns / Attributive Words (Rentaishi) (modify only taigen / nouns)
7. Conjunctions (Setsuzokushi) (connect sentences or phrases)
8. Interjections (Kandōshi) (express emotion, calls, or responses)
[Dependent Words (Fuzokugo)] (2 in total)
◆ Inflected
9. Auxiliary Verbs (Jodōshi) (add grammatical meaning and change their form)
◆ Uninflected
10. Particles (Joshi) (indicate relationships between words or add nuance, never change their form)
(*Detailed functions of particles and auxiliary verbs are covered in the chapter "Particles and Auxiliary Verbs.")
Step 4: Detailed Guide to Identifying the 10 Parts of Speech
1. Identifying Yōgen (Verbs, Adjectives, Adjectival Nouns)
All yōgen are "independent words" that "inflect." You can identify which one it is by looking at the final syllable of its dictionary form (conclusive form / base form).
- Verbs (Dōshi)
Words whose conclusive form ends in an u-row sound. They express actions, processes, or existence.
Examples: hashiru, yomu, hanasu, iku, aru
- Adjectives (Keiyōshi)
Words whose conclusive form ends in "i". They describe the nature or state of people and things.
Examples: takai (tall/expensive), utsukushii (beautiful), shiroi (white), samui (cold)
- Adjectival Nouns (Keiyōdōshi)
Words whose conclusive form ends in "da" or "desu". They express qualities or states.
Examples: shizuka da (quiet), shinsetsu da (kind), kirei da / kirei desu (pretty/clean)
[Common Mistake]
Many students mistakenly think "kirei da" is just the noun "kirei." However, because its ending changes depending on context—such as "kirei ni saku" or "kirei na hana"—and ends with "da" when completing a sentence, it is an adjectival noun (keiyōdōshi)!
2. Substantives (Nouns: Taigen)
- Nouns (Meishi)
These are "independent words" that "do not inflect."
They represent names of people, things, or concepts, and can form the grammatical subject by attaching "-ga" or "-wa".
Pronouns (such as "kore" [this], "anata" [you], "dare" [who]) are also classified as nouns.
Examples: sora (sky), Fujisan (Mt. Fuji), jiyū (freedom), gakkō (school), kare (he), soko (there)
3. Modifiers (Adverbs and Prenouns)
Both are "independent words" that "do not inflect," and both describe or explain other words in more detail (modify them). The decisive difference lies in what they modify.
- Adverbs (Fukushi)
They primarily modify yōgen (verbs, adjectives, and adjectival nouns).
They can describe manner or state (e.g., yukkuri [slowly], shikkari [firmly]) or degree (e.g., taihen [greatly], totemo [very]).
Examples: yukkuri aruku (modifies the verb "walk"), totemo samui (modifies the adjective "cold")
- Prenouns / Attributive Words (Rentaishi)
They only modify taigen (nouns). Remember them as "words linked to taigen" (ren-tai-shi). Their defining feature is that they never inflect.
Many of them end in sounds like "-no," "-ru," "-na," "-ta," or "-da/-shi."
Examples: ano hito (that person), ōkina ki (a big tree), arayuru bamen (every scene), taishita jinbutsu (a remarkable figure)
[Key Point: Super Important! The Difference Between "Ōkina" and "Ōkii"]
- "Ōkii" (large): Inflects (changes form into ōkikaro, ōkikatta...), making it an adjective (keiyōshi).
- "Ōkina" (large): You can say "ōkina tsukue" (a big desk), but it cannot conjugate into forms like "ōki-ni" or "ōki-da" (its form never changes), making it a prenoun (rentaishi)!
This is one of the most frequently tested distinctions on exams.
4. Other Independent Words (Conjunctions and Interjections)
- Conjunctions (Setsuzokushi)
These connect words, phrases, or clauses. They do not inflect.
Examples: dakara (therefore), shikashi (however), mata (furthermore/also), aruiwa (or)
(*The contextual roles of demonstrative words and conjunctive words are covered in detail in the chapter "Demonstratives and Conjunctions.")
- Interjections (Kandōshi)
Words that express sudden emotion, calling out to someone, greetings, or responding. They often stand independently at the beginning of a sentence and do not inflect.
Examples: ā (exclamation of emotion), moshimoshi (call/hello), hai (affirmative response), ohayō (greeting)
5. Dependent Words (Auxiliary Verbs and Particles)
These are words attached directly to the end of independent words.
- Auxiliary Verbs (Jodōshi)
Dependent words that inflect. They add meanings such as negation, past tense, politeness, conjecture, etc.
Examples: hashira-nai (negation), it-ta (past), yomi-masu (polite), ame-rashii (conjecture)
- Particles (Joshi)
Dependent words that do not inflect. They show grammatical relationships between words or add subtle shades of meaning.
Examples: sakura ga saku, ie e kaeru, hon mo yomu, hashiru na
[Trivia Tip]
When classifying Japanese words, verbs, adjectives, and adjectival nouns are collectively referred to as "yōgen" (declinable words / predicates), while nouns are called "taigen" (substantives). These two terms are essential vocabulary that appear constantly in high school entrance exams and grammar explanations!
The Decision Flowchart for Identifying Parts of Speech
Whenever you need to identify a part of speech, follow this order and you'll never go wrong!
Step A: Can it stand at the start of a phrase (bunsetsu)? (Does it make sense on its own?)
- YES → Go to Independent Words (Jiritsugo) (Proceed to Step B)
- NO → Go to Dependent Words (Fuzokugo) (Proceed to Step E)
Step B (Independent Words): Does its form change? (Does it inflect?)
- YES → Yōgen (Identify by its conclusive form!)
- Ends in an u-row sound → Verb (Dōshi)
- Ends in "i" → Adjective (Keiyōshi)
- Ends in "da" or "desu" → Adjectival Noun (Keiyōdōshi)
- NO → Go to Uninflected Independent Words (Proceed to Step C)
Step C (Uninflected Independent Words): Can it act as a subject? (Can "-ga" or "-wa" attach to it?)
- YES → Noun (Meishi)
- NO → Proceed to Step D
Step D (Independent Words that cannot be subjects): What is its function?
- Mainly modifies yōgen → Adverb (Fukushi)
- Exclusively modifies taigen (nouns) → Prenoun (Rentaishi)
- Connects words or sentences → Conjunction (Setsuzokushi)
- Expresses emotion, calls, replies, or greetings → Interjection (Kandōshi)
Step E (Dependent Words): Does its form change? (Does it inflect?)
- YES → Auxiliary Verb (Jodōshi) (e.g., nai, ta, masu, da, rashii)
- NO → Particle (Joshi) (e.g., ga, o, ni, wa, kara, node)
Let's Check Your Understanding with Practice Questions!
Identify the part of speech for each underlined word in the sentence below:
"Asoko ni chiisana hana ga utsukushiku sai ta." (A small flower bloomed beautifully over there.)
[Walkthrough and Answers]
- Asoko (over there): Independent word, uninflected, can take "-ga" to become a subject ("asoko ga...") representing a location name (pronoun) → Noun (Meishi)
- Chiisana (small): Independent word that modifies only "hana" (a noun) and never inflects → Prenoun (Rentaishi)
- Utsukushiku (beautifully): Independent word whose form changes, and its conclusive form ends in "utsukushii" → Adjective (Keiyōshi)
- Sai (bloomed / bloom): Independent word whose form changes, and its conclusive form ends in "saku" (an u-row sound) → Verb (Dōshi)
- Ta (past marker): Dependent word attached to an independent word that inflects (e.g., ta, tara, darō) to express past tense → Auxiliary Verb (Jodōshi)
[Summary]
The secret to mastering parts of speech is systematically narrowing down each word in this order: "Independent or Dependent?" → "Inflected or Uninflected?" → "Conclusive form or function in the sentence." Take your time, practice using these steps, and you'll turn grammar into one of your strongest skills!